High Memory corruption exploit reference

CVE-2026-25556 — MuPDF 1.23.0 through 1.27.0 Barcode Decoding Double Free

MuPDF versions 1.23.0 through 1.27.0 contain a double-free vulnerability in fz_fill_pixmap_from_display_list() when an exception occurs during display list rendering. The function accepts a caller-owned fz_pixmap pointer but incorrectly drops the pixmap in its error handling path before rethrowing the exception. Callers (including the barcode decoding path in fz_decode_barcode_from_display_list) also drop the same pixmap in cleanup, resulting in a double-free that can corrupt the heap and crash the process. This issue affects applications that enable and use MuPDF barcode decoding and can be triggered by processing crafted input that causes a rendering-time error while decoding barcodes.

Published Feb 6, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: VulnCheck

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.8% (30-day exploitation probability)+8
Technical severity (high)+6
CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.77%

ahead of 55% of scored CVEs · Oct 15, 2026

Affects

Artifex

Mupdf and 1 more

CVSS base

7.5

High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — cgit.ghostscript.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Artifex Mupdf, Artifex Software MuPDF).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Artifex	Mupdf	≥ 1.23.0 and ≤ 1.27.0	Vulnerable	NIST National Vulnerability Database
Artifex Software	MuPDF	≥ 1.23.0 and ≤ 1.27.0	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.9	CVSS 4.0	Medium	—	—	disclosure@vulncheck.com via NIST National Vulnerability Database
5.9	CVSS 4.0	Medium	—	—	VulnCheck via CVE Program (cve.org) e CISA ADP
7.5	CVSS 3.1	High	3.9	3.6	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-415 · Double Free

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.77%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · artifex software/mupdf
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 7.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Feb 6, 2026 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

cgit.ghostscript.com/cgi-bin/cgit.cgi/mupdf.git/commit/
Patch, patch, NIST National Vulnerability Database
mupdf.com/
Product, product, NIST National Vulnerability Database
www.vulncheck.com/advisories/mupdf-barcode-decoding-double-free
Third Party Advisory, third-party-advisory, NIST National Vulnerability Database
bugs.ghostscript.com/show_bug.cgi
Exploit, Issue Tracking, issue-tracking, NIST National Vulnerability Database

Elsewhere on this site

Artifex
every CVE for this vendor

Memory corruption
same class

CWE-415
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-92413 Artifex MuPDF PDF Xref Loading pdf-stream.c pdf_open_filter null pointer dereference 29d
Medium CVE-2025-71382 MuPDF < 1.27.0-rc1 Stack Exhaustion DoS via EPUB CSS Rendering Jun 23, 2026
Medium CVE-2026-7233 Artifex MuPDF CFF Index subset-cff.c fz_subset_cff_for_gids out-of-bounds Apr 28, 2026
Low CVE-2026-40505 MuPDF < 1.27 mutool ANSI Injection via Metadata Apr 15, 2026
High CVE-2025-15569 Artifex MuPDF win_main.c get_system_dpi uncontrolled search path Feb 10, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-25556 is "MuPDF 1.23.0 through 1.27.0 Barcode Decoding Double Free", rated High. It affects Mupdf (Artifex); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.77% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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