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Full vulnerability report · 2026
CVE-2026-62377High confidence

libheif: Reachable assertion in HeifContext::get_track() aborts on a valid-but-empty HEIF sequence file (context.cc:2110)

strukturag · libheif

4.3MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-62377 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitylibheif: libheif: Denial of Service via crafted HEIF sequence
1 known not affected

The vendor explicitly states that these products are not affected by this CVE.

  • All currently supported Red Hat products
Summary
A flaw was found in libheif, a HEIF and AVIF file format decoder and encoder. A remote attacker could provide a specially crafted HEIF sequence. Processing this malicious file could lead to a reachable assertion or dereference an empty map, resulting in a crash of the application. This vulnerability can cause a Denial of Service (DoS).
Remediation
No remediation text is recorded.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-62191

No EUVD known-exploited evidence

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heif_context_read_from_memory() can leave the context with no registered sequence tracks and crash when heif_context_get_track(ctx, 0) is called. HeifContext::get_track() in libheif/context.cc executes assert(has_sequence()) before its normal error handling, so assert-enabled builds abort instead of allowing the public wrapper in libheif/api/libheif/heif_sequences.cc to return null. In release builds, removing the assertion lets the track_id zero path dereference m_tracks.begin()->second on an empty map, which is undefined behavior and typically crashes. The issue is reachable through documented public APIs after parsing attacker-controlled bytes. This issue is fixed in version 1.23.1.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
4.3 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heif_context_read_from_memory() can leave the context with no registered sequence tracks and crash when heif_context_get_track(ctx, 0) is called. HeifContext::get_track() in libheif/context.cc executes assert(has_sequence()) before its normal error handling, so assert-enabled builds abort instead of allowing the public wrapper in libheif/api/libheif/heif_sequences.cc to return null. In release builds, removing the assertion lets the track_id zero path dereference m_tracks.begin()->second on an empty map, which is undefined behavior and typically crashes. The issue is reachable through documented public APIs after parsing attacker-controlled bytes. This issue is fixed in version 1.23.1.

What

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heif_context_read_from_memory() can leave the context with no registered sequence tracks and crash when heif_context_get_track(ctx, 0) is called. HeifContext::get_track() in libheif/context.cc executes assert(has_sequence()) before its normal error handling, so assert-enabled builds abort instead of allowing the public wrapper in libheif/api/libheif/heif_sequences.cc to return null. In release builds, removing the assertion lets the track_id zero path dereference m_tracks.begin()->second on an empty map, which is undefined behavior and typically crashes. The issue is reachable through documented public APIs after parsing attacker-controlled bytes. This issue is fixed in version 1.23.1.

Why

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may disrupt the affected service.

What

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heif_context_read_from_memory() can leave the context with no registered sequence tracks and crash when heif_context_get_track(ctx, 0) is called. HeifContext::get_track() in libheif/context.cc executes assert(has_sequence()) before its normal error handling, so assert-enabled builds abort instead of allowing the public wrapper in libheif/api/libheif/heif_sequences.cc to return null. In release builds, removing the assertion lets the track_id zero path dereference m_tracks.begin()->second on an empty map, which is undefined behavior and typically crashes. The issue is reachable through documented public APIs after parsing attacker-controlled bytes. This issue is fixed in version 1.23.1.

Why

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Reachable Assertion → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-617 ↗

CWE-617: Reachable Assertion. The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-617
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-62191Official EUVD mapping

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heif_context_read_from_memory() can leave the context with no registered sequence tracks and crash when heif_context_get_track(ctx, 0) is called. HeifContext::get_track() in libheif/context.cc executes assert(has_sequence()) before its normal error handling, so assert-enabled builds abort instead of allowing the public wrapper in libheif/api/libheif/heif_sequences.cc to return null. In release builds, removing the assertion lets the track_id zero path dereference m_tracks.begin()->second on an empty map, which is undefined behavior and typically crashes. The issue is reachable through documented public APIs after parsing attacker-controlled bytes. This issue is fixed in version 1.23.1.

Official EUVD record
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
< 1.23.1
Fixed
1.23.1.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 18 Aug 2026 · Last source change 19 Aug 2026, 18:19 UTC · CWE-617 · Reachable Assertion

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-23
European sourceENISA EUVD · EUVD-2026-62191
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →
  1. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-62191↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-62377 · cve.blacktree.nl