ETK-2026-2691Zero's internal tracking ID, independent of the CVE number.

waiting for further signalsZero needs more public information before it can validate it.

GHSA-rcqc-842v-m26h ↗

no check availablenot proven exploitable
awaiting cvepublic pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).kevAttacks confirmed in the real world.
other libheif >= 1.21.0, < 1.23.7
fixed in 1.23.7
CWE-833 Deadlock
ETK-2026-2691Zero's internal tracking ID, independent of the CVE number., no cve assigned
6h 06msince last run
30mAI analysisAnalysis: how long the AI spent reversing this signal.
timeline
0 = cve.org, not yet published
trigger signal −14h19mwaiting for further signals−6h06m
−12h
−9h
−3h
0

description

libheif versions 1.21.0 through 1.23.6 can deadlock while processing malformed HEIF grid images with parallel decoding enabled. An attacker who can supply a HEIF file to an application using the affected decoder can cause the image-processing task or worker to remain blocked.

mitigation

Upgrade libheif to version 1.23.7 or later. Until upgraded, use strict or single-threaded decoding for untrusted HEIF files where those options are available.

fixed in 1.23.7

check
no
exploit
no
automationDeterministic: a check that runs on its own, the same request on every target. Contextual: an agentic technique that needs to be applied per target, for bugs that depend on contextual flows.
contextual
auth requiredWhether an attacker needs an account first, based on the CVSS vector's Privileges Required.
no
EPSSEstimate of the chance this CVE is exploited in the next 30 days. Refreshed daily.
–
agent run time
30m
cve.org record, t = 0The moment cve.org publishes the CVE in full.
not published yet
Δ to public pocExploit code has been published by someone. Source signals can also carry a PoC (Proof of Concept).
–
Δ to kevAttacks confirmed in the real world.
–

outcome

Contextual, not validated: no deterministic check could cover this one, and no technique passed our review.

source signals

Public signals that triggered or updated the pipeline. These are inputs for the deltas above.

  1. 2026-10-26 11:51Z

this entry in the feed

GET /api/v1/feed/ETK-2026-2691

{
  "etk_id": "ETK-2026-2691",
  "cve_id": null,
  "display_id": "ETK-2026-2691",
  "ghsa_id": "GHSA-rcqc-842v-m26h",
  "euvd_id": null,
  "status": "published",
  "anchor_state": "awaiting_cve",
  "title": "Parallel HEIF grid decoding deadlock in libheif",
  "summary": "libheif versions 1.21.0 through 1.23.6 can deadlock while processing malformed HEIF grid images with parallel decoding enabled. An attacker who can supply a HEIF file to an application using the affected decoder can cause the image-processing task or worker to remain blocked.",
  "mitigation": "Upgrade libheif to version 1.23.7 or later. Until upgraded, use strict or single-threaded decoding for untrusted HEIF files where those options are available.",
  "vendor": "other",
  "product": "libheif",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 1.21.0, < 1.23.7"
      ],
      "ecosystem": "other",
      "fixed_versions": [
        "1.23.7"
      ],
      "package_name": "libheif",
      "purl": null
    }
  ],
  "cwes": [
    833
  ],
  "cvss_score": 7.5,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "contextual",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 30.412414633333334,
  "t0_at": null,
  "signals": {
    "trigger_signal": {
      "at": "2026-10-26T11:51:38+00:00",
      "days": -0.5965726012268519,
      "is_lower_bound": true,
      "measured_at": "2026-10-27T02:10:41.902181+00:00",
      "url": "https://github.com/strukturag/libheif/security/advisories/GHSA-rcqc-842v-m26h"
    }
  }
}

published 2026-10-26 20:40Z
last change 2026-10-27 01:41Z

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