Vulnerability-Lookup

CVE-2026-54899 (GCVE-0-2026-54899)

Vulnerability from cvelistv5 – Published: 2026-06-30 23:03 – Updated: 2026-07-01 14:26

Title

Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle

Summary

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to version 3.17.2, disabling symbol_keys on a reused Oj::Parser instance triggers a heap use-after-free. When symbol_keys is toggled from true to false, opt_symbol_keys_set frees the internal key cache (cache_free) but does not clear the pointer. The next parse call reads from the freed cache via cache_intern, producing a use-after-free. This issue has been fixed in version 3.17.2.

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-416 - Use After Free

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/ohler55/oj/security/advisories…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
ohler55	oj	Affected: < 3.17.2

Show details on NVD website

JSON

To clipboard

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      "title": "Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle"
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  }
}

FKIE_CVE-2026-54899

Vulnerability from fkie_nvd - Published: 2026-07-01 00:16 - Updated: 2026-07-01 15:27

Severity

6.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/ohler55/oj/security/advisories/GHSA-2cw7-v8ff-p88r
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/ohler55/oj/security/advisories/GHSA-2cw7-v8ff-p88r

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "oj",
          "vendor": "ohler55",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.17.2"
            }
          ]
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      "source": "security-advisories@github.com"
    }
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to version 3.17.2, disabling symbol_keys on a reused Oj::Parser instance triggers a heap use-after-free. When symbol_keys is toggled from true to false, opt_symbol_keys_set frees the internal key cache (cache_free) but does not clear the pointer. The next parse call reads from the freed cache via cache_intern, producing a use-after-free. This issue has been fixed in version 3.17.2."
    }
  ],
  "id": "CVE-2026-54899",
  "lastModified": "2026-07-01T15:27:14.107",
  "metrics": {
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          "Recovery": "NOT_DEFINED",
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          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "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": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/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": "LOW",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
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        "type": "Secondary"
      }
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  "references": [
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      "source": "security-advisories@github.com",
      "url": "https://github.com/ohler55/oj/security/advisories/GHSA-2cw7-v8ff-p88r"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/ohler55/oj/security/advisories/GHSA-2cw7-v8ff-p88r"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
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    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-2CW7-V8FF-P88R

Vulnerability from github – Published: 2026-06-19 19:34 – Updated: 2026-06-19 19:34

Summary

Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle

Details

Summary

Disabling symbol_keys on a reused Oj::Parser instance triggers a heap use-after-free. When symbol_keys is toggled from true to false, opt_symbol_keys_set frees the internal key cache (cache_free) but does not clear the pointer. The next parse call reads from the freed cache via cache_intern, producing a use-after-free.

Version

Software: oj gem
Affected: all versions with ext/oj/usual.c
Latest tested: 3.17.1 (confirmed present)

Details

ext/oj/usual.c, opt_symbol_keys_set:

// usual.c:1043–1051
if (symbol_keys) {
    d->key_cache = cache_create(...);   // allocate
} else {
    cache_free(d->key_cache);           // free — but d->key_cache pointer not NULLed
}

On the next parse call, cache_key → cache_intern reads from d->key_cache which now points to freed memory.

ASAN report:

==145265==ERROR: AddressSanitizer: heap-use-after-free on address 0x50b00001a318
READ of size 8 at 0x50b00001a318 thread T0
    #0 cache_intern            /ext/oj/cache.c:328
    #1 cache_key               /ext/oj/usual.c:161
    #2 close_object            /ext/oj/usual.c:285
    #3 parse                   /ext/oj/parser.c:693
    #4 parser_parse            /ext/oj/parser.c:1408
freed by thread T0 here:
    #0 free
    #1 cache_free              /ext/oj/cache.c:277
    #2 opt_symbol_keys_set     /ext/oj/usual.c:1051
    #3 option                  /ext/oj/usual.c:1111
    #4 parser_missing          /ext/oj/parser.c:1362
0x50b00001a318 is 40 bytes inside freed 112-byte region [fd]fd fd fd fd fd fd fd

Reproduce

require 'oj'
p = Oj::Parser.new(:usual, symbol_keys: true)
p.symbol_keys = false     # frees cache without nulling pointer
p.parse('{"attacker":1}') # UAF: reads freed cache

Severity

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 3.17.2"
      },
      "package": {
        "ecosystem": "RubyGems",
        "name": "oj"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.17.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54899"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T19:34:30Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nDisabling `symbol_keys` on a reused `Oj::Parser` instance triggers a heap use-after-free. When `symbol_keys` is toggled from `true` to `false`, `opt_symbol_keys_set` frees the internal key cache (`cache_free`) but does not clear the pointer. The next `parse` call reads from the freed cache via `cache_intern`, producing a use-after-free.\n\n### Version\n\n- **Software**: oj gem\n- **Affected**: all versions with `ext/oj/usual.c`\n- **Latest tested**: 3.17.1 (confirmed present)\n\n### Details\n\n`ext/oj/usual.c`, `opt_symbol_keys_set`:\n\n```c\n// usual.c:1043\u20131051\nif (symbol_keys) {\n    d-\u003ekey_cache = cache_create(...);   // allocate\n} else {\n    cache_free(d-\u003ekey_cache);           // free \u2014 but d-\u003ekey_cache pointer not NULLed\n}\n```\n\nOn the next parse call, `cache_key` \u2192 `cache_intern` reads from `d-\u003ekey_cache` which now points to freed memory.\n\nASAN report:\n```\n==145265==ERROR: AddressSanitizer: heap-use-after-free on address 0x50b00001a318\nREAD of size 8 at 0x50b00001a318 thread T0\n    #0 cache_intern            /ext/oj/cache.c:328\n    #1 cache_key               /ext/oj/usual.c:161\n    #2 close_object            /ext/oj/usual.c:285\n    #3 parse                   /ext/oj/parser.c:693\n    #4 parser_parse            /ext/oj/parser.c:1408\nfreed by thread T0 here:\n    #0 free\n    #1 cache_free              /ext/oj/cache.c:277\n    #2 opt_symbol_keys_set     /ext/oj/usual.c:1051\n    #3 option                  /ext/oj/usual.c:1111\n    #4 parser_missing          /ext/oj/parser.c:1362\n0x50b00001a318 is 40 bytes inside freed 112-byte region [fd]fd fd fd fd fd fd fd\n```\n\n### Reproduce\n\n```ruby\nrequire \u0027oj\u0027\np = Oj::Parser.new(:usual, symbol_keys: true)\np.symbol_keys = false     # frees cache without nulling pointer\np.parse(\u0027{\"attacker\":1}\u0027) # UAF: reads freed cache\n```",
  "id": "GHSA-2cw7-v8ff-p88r",
  "modified": "2026-06-19T19:34:30Z",
  "published": "2026-06-19T19:34:30Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/ohler55/oj/security/advisories/GHSA-2cw7-v8ff-p88r"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ohler55/oj"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle"
}

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

CVE-2026-54899 (GCVE-0-2026-54899)

FKIE_CVE-2026-54899

GHSA-2CW7-V8FF-P88R

Summary

Version

Details

Reproduce

Tags

Sightings

Nomenclature