‹ Back to list

CVE-2026-91186

Status: ReceivedHigh (8.4)—
Severity8.4High · CVSS 4.0
Exploitation probability—next 30 days
Active exploitationNonot in the CISA catalog
Public exploitNot knownno public code found

The PNG chunk reader has no notion of chunk ordering. It records whether an IDAT has been seen and whether a tRNS has already supplied transparency, but nothing prevents an IHDR being read a second time.

A PNG carries exactly one IHDR and it is the first chunk. A file that places a second one after IDAT rewrites the image width, height, bit depth and pixel depth *after* the decoded-data buffer has already been allocated and filled from the original values. The pass that reverses the PNG row filters then derives its own extent from the new dimensions and walks the old allocation, moving image bytes past the end of it.

Read full descriptionShow less

The buffer is allocated by GUIX rather than supplied by the caller, so the application has no way to size it defensively. The decoder is compiled in by default.

CVSS

Base score
8.4
Version
4.0
Vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/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

Exploitation probability (EPSS)

FIRST hasn't scored this CVE yet (usual for very recent or rejected CVEs).

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Inferred by deterministic rules from the CVSS vector and CWE. Indicative only.

ATT&CK mitigations that cover these techniques

Restrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationExecution PreventionBehavior Prevention on EndpointDisable or Remove Feature or Program

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

GNU — GuixAI

CWEs

References

Show 1 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-91186",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-91186",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-10-20T15:28:30.798866Z"
        }
      }
    ],
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "emo@eclipse.org",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 8.4,
          "Automatable": "NOT_DEFINED",
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/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",
          "exploitMaturity": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED",
          "userInteraction": "ACTIVE",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
        }
      }
    ]
  },
  "affected": [
    {
      "source": "emo@eclipse.org",
      "affectedData": [
        {
          "vendor": "Eclipse Foundation",
          "product": "Eclipse ThreadX - GUIX",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "6.5.1.202602a"
            },
            {
              "status": "unaffected",
              "version": "6.5.2.202603"
            }
          ],
          "packageName": "GUIX",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-10-20T15:17:36.023",
  "references": [
    {
      "url": "https://github.com/eclipse-threadx/guix/security/advisories/GHSA-gx8f-4rpc-4fjw",
      "source": "emo@eclipse.org"
    }
  ],
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "emo@eclipse.org",
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        },
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "The PNG chunk reader has no notion of chunk ordering. It records whether an IDAT has been seen and whether a tRNS has already supplied transparency, but nothing prevents an IHDR being read a second time.\n\n\n\nA PNG carries exactly one IHDR and it is the first chunk. A file that places a second one after IDAT rewrites the image width, height, bit depth and pixel depth *after* the decoded-data buffer has already been allocated and filled from the original values. The pass that reverses the PNG row filters then derives its own extent from the new dimensions and walks the old allocation, moving image bytes past the end of it.\n\n\n\nThe buffer is allocated by GUIX rather than supplied by the caller, so the application has no way to size it defensively. The decoder is compiled in by default."
    }
  ],
  "lastModified": "2026-10-20T16:17:16.490",
  "sourceIdentifier": "emo@eclipse.org"
}