Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/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:XSummary
CVE-2026-25556 is a medium-severity Double Free (CWE-415) vulnerability in Artifex Mupdf. Its CVSS base score is 5.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 39th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
MuPDF versions 1.23.0 through 1.27.0 are affected by CVE-2026-25556, a double-free vulnerability (CWE-415) in the fz_fill_pixmap_from_display_list() function. The issue arises when an exception occurs during display list rendering, as the function accepts a caller-owned fz_pixmap pointer but incorrectly drops it in the error handling path before rethrowing the exception. Callers, such as the barcode decoding path in fz_decode_barcode_from_display_list(), also drop the same pixmap during cleanup, leading to heap corruption and process crashes. This vulnerability impacts applications that enable and use MuPDF's barcode decoding feature.
The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), indicating high availability impact with network accessibility, low attack complexity, and no privileges or user interaction required. Attackers can exploit it remotely by supplying crafted input, such as a malicious barcode, that triggers a rendering-time error during barcode decoding. Successful exploitation results in heap corruption and denial-of-service via process crash, affecting any vulnerable MuPDF-integrated application processing untrusted inputs.
Mitigation is available through a patch commit (d4743b6092d513321c23c6f7fe5cff87cde043c1) in the MuPDF Git repository, as documented in the Ghostscript bug tracker (bug 709029) and a Vulncheck advisory. Security practitioners should update to a patched MuPDF version beyond 1.27.0 and review applications using barcode decoding features for exposure to malicious PDF or image inputs. Additional details are available on the MuPDF website.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5668
Vulnerability Data
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.…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 1 hardening rule · 1 OS baseline
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation explicitly includes dynamic analysis and fuzzing that locate double-free defects before release.
Security engineering principles can require memory-safe allocation patterns or language features that structurally eliminate double-free opportunities.
Flaw remediation processes require identification and correction of memory-management defects such as double free once discovered.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent double-free errors via static analysis, safe memory APIs, and testing.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect double-free conditions before release.
Secure development life cycle includes memory-safety practices that can prevent double-free bugs.
Application security requirements can mandate memory-safety rules that reduce double-free risk.
Secure system architecture and engineering principles can prescribe safe memory-management patterns.
Secure coding standards directly address proper use of free() and similar functions.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248590 OL 8 must clear the page allocator to prevent use-after-free attacks. prevents CWE-415