Vulnerability-Lookup

GHSA-F7P3-6RHJ-P7JV

Vulnerability from github – Published: 2026-04-28 09:34 – Updated: 2026-04-28 09:34

Details

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parse_message.

Severity ?

5.9 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

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  "affected": [],
  "aliases": [
    "CVE-2026-40356"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-191"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-28T07:16:03Z",
    "severity": "MODERATE"
  },
  "details": "In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parse_message.",
  "id": "GHSA-f7p3-6rhj-p7jv",
  "modified": "2026-04-28T09:34:12Z",
  "published": "2026-04-28T09:34:12Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40356"
    },
    {
      "type": "WEB",
      "url": "https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f"
    },
    {
      "type": "WEB",
      "url": "https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html"
    },
    {
      "type": "WEB",
      "url": "https://web.mit.edu/kerberos/advisories"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-40356 (GCVE-0-2026-40356)

Vulnerability from cvelistv5 – Published: 2026-04-28 00:00 – Updated: 2026-04-28 13:10

Summary

Severity ?

5.9 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE

CWE-191 - Integer Underflow (Wrap or Wraparound)

Assigner

mitre

References

3 references

URL	Tags
https://web.mit.edu/kerberos/advisories/
https://cems.fun/2026/04/27/krb5-two-unauthentica…
https://github.com/krb5/krb5/commit/2e75f0d9362fb…

Impacted products

1 product

Vendor	Product	Version
MIT	Kerberos 5	Affected: 1.18 , < 1.22.3 (custom)

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JSON

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        "metrics": [
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                "id": "CVE-2026-40356",
                "options": [
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                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
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                "role": "CISA Coordinator",
                "timestamp": "2026-04-28T13:10:05.740836Z",
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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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-F7P3-6RHJ-P7JV

CVE-2026-40356 (GCVE-0-2026-40356)

Tags

Sightings

Nomenclature