CVE-2026-121550 (GCVE-0-2026-121550)

Vulnerability from cvelistv5 – Published: 2026-11-03 15:17 – Updated: 2026-11-03 15:17
VLAI
Title
nnn through 5.3 Symlink-Following Write via NNN_FIFO Handling
Summary
nnn through 5.3 contains an insecure file handling vulnerability that allows local attackers to redirect writes because main() accepts an existing NNN_FIFO path without verifying it is a FIFO. Attackers can pre-create the documented predictable /tmp/nnn.fifo path as a symlink or readable regular file, causing victim-writable files to be overwritten or leaking the victim's browsed paths.
Severity
1 (Low)
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
3.3 (Low)
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
CWE
  • CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 7402 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
jarun nnn Affected: 0 , ≤ 5.3 (custom)
guessed Create a notification for this product.
Date Public
2026-10-31 00:00
Credits
George Chen
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "nnn",
          "vendor": "jarun",
          "versions": [
            {
              "lessThanOrEqual": "5.3",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "George Chen"
        }
      ],
      "datePublic": "2026-10-31T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "nnn through 5.3 contains an insecure file handling vulnerability that allows local attackers to redirect writes because main() accepts an existing NNN_FIFO path without verifying it is a FIFO. Attackers can pre-create the documented predictable /tmp/nnn.fifo path as a symlink or readable regular file, causing victim-writable files to be overwritten or leaking the victim\u0027s browsed paths."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 1,
            "baseSeverity": "LOW",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "ACTIVE",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "LOW"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 3.3,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-03T15:17:09.442Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Issue #2188",
          "tags": [
            "issue-tracking"
          ],
          "url": "https://github.com/jarun/nnn/issues/2188"
        },
        {
          "tags": [
            "product"
          ],
          "url": "https://github.com/jarun/nnn"
        },
        {
          "name": "Fix commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/jarun/nnn/commit/04715921aece0257fef7a8558c0783493d98efff"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L10635"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L7433"
        },
        {
          "name": "VulnCheck Advisory: nnn through 5.3 Symlink-Following Write via NNN_FIFO Handling",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/nnn-through-5.3-symlink-following-write-via-nnn-fifo-handling"
        }
      ],
      "title": "nnn through 5.3 Symlink-Following Write via NNN_FIFO Handling",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-121550",
    "datePublished": "2026-11-03T15:17:09.442Z",
    "dateReserved": "2026-11-03T14:46:14.575Z",
    "dateUpdated": "2026-11-03T15:17:09.442Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-121550",
      "date": "2026-11-04",
      "epss": "0.00116",
      "percentile": "0.01619"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "nnn",
                "vendor": "jarun",
                "versions": [
                  {
                    "lessThanOrEqual": "5.3",
                    "status": "affected",
                    "version": "0",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "source": "disclosure@vulncheck.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "nnn through 5.3 contains an insecure file handling vulnerability that allows local attackers to redirect writes because main() accepts an existing NNN_FIFO path without verifying it is a FIFO. Attackers can pre-create the documented predictable /tmp/nnn.fifo path as a symlink or readable regular file, causing victim-writable files to be overwritten or leaking the victim\u0027s browsed paths."
          }
        ],
        "id": "CVE-2026-121550",
        "lastModified": "2026-11-03T16:30:17.150",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "LOCAL",
                "availabilityImpact": "NONE",
                "baseScore": 3.3,
                "baseSeverity": "LOW",
                "confidentialityImpact": "LOW",
                "integrityImpact": "LOW",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 0.8,
              "impactScore": 2.5,
              "source": "disclosure@vulncheck.com",
              "type": "Primary"
            }
          ],
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "PRESENT",
                "attackVector": "LOCAL",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 1.0,
                "baseSeverity": "LOW",
                "confidentialityRequirement": "NOT_DEFINED",
                "exploitMaturity": "NOT_DEFINED",
                "integrityRequirement": "NOT_DEFINED",
                "modifiedAttackComplexity": "NOT_DEFINED",
                "modifiedAttackRequirements": "NOT_DEFINED",
                "modifiedAttackVector": "NOT_DEFINED",
                "modifiedPrivilegesRequired": "NOT_DEFINED",
                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
                "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
                "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
                "modifiedVulnIntegrityImpact": "NOT_DEFINED",
                "privilegesRequired": "LOW",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "ACTIVE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "LOW",
                "vulnIntegrityImpact": "LOW",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "source": "disclosure@vulncheck.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-11-03T16:17:26.897",
        "references": [
          {
            "source": "disclosure@vulncheck.com",
            "url": "https://github.com/jarun/nnn"
          },
          {
            "source": "disclosure@vulncheck.com",
            "url": "https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L10635"
          },
          {
            "source": "disclosure@vulncheck.com",
            "url": "https://github.com/jarun/nnn/blob/v5.3/src/nnn.c#L7433"
          },
          {
            "source": "disclosure@vulncheck.com",
            "url": "https://github.com/jarun/nnn/commit/04715921aece0257fef7a8558c0783493d98efff"
          },
          {
            "source": "disclosure@vulncheck.com",
            "url": "https://github.com/jarun/nnn/issues/2188"
          },
          {
            "source": "disclosure@vulncheck.com",
            "url": "https://www.vulncheck.com/advisories/nnn-through-5.3-symlink-following-write-via-nnn-fifo-handling"
          }
        ],
        "sourceIdentifier": "disclosure@vulncheck.com",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-59"
              }
            ],
            "source": "disclosure@vulncheck.com",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-11-03T19:41:12+00:00",
      "cve": "CVE-2026-121550",
      "id": "CVE-2026-121550",
      "initial_release_date": "2026-11-03T15:17:09.442000+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "nnn: nnn: arbitrary file overwrite via insecure FIFO path handling",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-121550.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.