ExifReader: DoS via Crafted HEIC/AVIF iloc Box - Memory Exhaustion
mattiasw · ExifReader
Official source article: GitHub GHSA-PJ96-35FP-CFCC ↗. Check the applicable product and release in the original source.
7.5HighCVSS 3.1
Recommended action
Within 7 days
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
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-2026-81897
No EUVD known-exploited evidence
ExifReader is a JavaScript Exif information parser. Prior to 4.41.1, ExifReader parses attacker-controlled HEIC or AVIF ISO-BMFF files in getItems() within src/image-header-iso-bmff-iloc.js and trusts iloc itemCount and extentCount values while allocating an extent object for every nested-loop iteration. When offsetSize, lengthSize, baseOffsetSize, and indexSize are zero, the extent fields consume no input bytes and the buffer offset does not advance, but the parser can still allocate up to itemCount multiplied by extentCount objects without an allocation budget. A small malicious iloc box can therefore cause hundreds of megabytes of heap growth or exhaust system memory, terminating a Node.js process and denying service to web, desktop, or mobile applications that parse untrusted images. The zero field widths are valid ISO-BMFF values indicating absent fields, so the vulnerable parser must bound work rather than relying on offset advancement. The issue is fixed in version 4.41.1.
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
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Patch available
01
What, why and how
ExifReader is a JavaScript Exif information parser. Prior to 4.41.1, ExifReader parses attacker-controlled HEIC or AVIF ISO-BMFF files in getItems() within src/image-header-iso-bmff-iloc.js and trusts iloc itemCount and extentCount values while allocating an extent object for every nested-loop iteration. When offsetSize, lengthSize, baseOffsetSize, and indexSize are zero, the extent fields consume no input bytes and the buffer offset does not advance, but the parser can still allocate up to itemCount multiplied by extentCount objects without an allocation budget. A small malicious iloc box can therefore cause hundreds of megabytes of heap growth or exhaust system memory, terminating a Node.js process and denying service to web, desktop, or mobile applications that parse untrusted images. The zero field widths are valid ISO-BMFF values indicating absent fields, so the vulnerable parser must bound work rather than relying on offset advancement. The issue is fixed in version 4.41.1.
What
ExifReader is a JavaScript Exif information parser. Prior to 4.41.1, ExifReader parses attacker-controlled HEIC or AVIF ISO-BMFF files in getItems() within src/image-header-iso-bmff-iloc.js and trusts iloc itemCount and extentCount values while allocating an extent object for every nested-loop iteration. When offsetSize, lengthSize, baseOffsetSize, and indexSize are zero, the extent fields consume no input bytes and the buffer offset does not advance, but the parser can still allocate up to itemCount multiplied by extentCount objects without an allocation budget. A small malicious iloc box can therefore cause hundreds of megabytes of heap growth or exhaust system memory, terminating a Node.js process and denying service to web, desktop, or mobile applications that parse untrusted images. The zero field widths are valid ISO-BMFF values indicating absent fields, so the vulnerable parser must bound work rather than relying on offset advancement. The issue is fixed in version 4.41.1.
Why
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
ExifReader is a JavaScript Exif information parser. Prior to 4.41.1, ExifReader parses attacker-controlled HEIC or AVIF ISO-BMFF files in getItems() within src/image-header-iso-bmff-iloc.js and trusts iloc itemCount and extentCount values while allocating an extent object for every nested-loop iteration. When offsetSize, lengthSize, baseOffsetSize, and indexSize are zero, the extent fields consume no input bytes and the buffer offset does not advance, but the parser can still allocate up to itemCount multiplied by extentCount objects without an allocation budget. A small malicious iloc box can therefore cause hundreds of megabytes of heap growth or exhaust system memory, terminating a Node.js process and denying service to web, desktop, or mobile applications that parse untrusted images. The zero field widths are valid ISO-BMFF values indicating absent fields, so the vulnerable parser must bound work rather than relying on offset advancement. The issue is fixed in version 4.41.1.
Why
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
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.Reference recorded
CISA Vulnrichment records proof-of-concept exploitation in its SSVC data. BlackTree has not independently executed or validated exploit material.
Likely attack path
a network path → Memory Allocation with Excessive Size Value → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
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-789: Memory Allocation with Excessive Size Value. The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
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:N/S:U/C:N/I:N/A:H
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.UINoneUser interaction: No action by another user is required.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.AHighAvailability impact: A successful attack can cause a major 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.
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2026-81897Official EUVD mapping
ExifReader is a JavaScript Exif information parser. Prior to 4.41.1, ExifReader parses attacker-controlled HEIC or AVIF ISO-BMFF files in getItems() within src/image-header-iso-bmff-iloc.js and trusts iloc itemCount and extentCount values while allocating an extent object for every nested-loop iteration. When offsetSize, lengthSize, baseOffsetSize, and indexSize are zero, the extent fields consume no input bytes and the buffer offset does not advance, but the parser can still allocate up to itemCount multiplied by extentCount objects without an allocation budget. A small malicious iloc box can therefore cause hundreds of megabytes of heap growth or exhaust system memory, terminating a Node.js process and denying service to web, desktop, or mobile applications that parse untrusted images. The zero field widths are valid ISO-BMFF values indicating absent fields, so the vulnerable parser must bound work rather than relying on offset advancement. The issue is fixed in version 4.41.1.
Official EUVD record ↗Cyber Security Agency of Singapore · English · CSA-SB-20260923Security Bulletin 23 Sep 2026
The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 23 Sep 2026, published on 23 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.
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.
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 17 Sept 2026 · Last source change 17 Sept 2026, 15:54 UTC · CWE-789 · Memory Allocation with Excessive Size Value
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 2026-09-18
European sourceENISA EUVD · EUVD-2026-81897
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD awaiting enrichment
Core structured fields are present and their contributing authorities are shown above.
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.