CVE-2026-40260
Pypdf Project Pypdf ≤ 6.10.0
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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-2026-40260 is a medium-severity XML Entity Expansion (CWE-776) vulnerability in Pypdf Project Pypdf. Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 35th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-23327
Vulnerability Data
pypdf is a free and open-source pure-python PDF library. In versions prior to 6.10.0, manipulated XMP metadata entity declarations can exhaust RAM. An attacker who exploits this vulnerability can craft a PDF which leads to large memory usage. This requires…
more
parsing the XMP metadata. This issue has been fixed in version 6.10.0.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Secure configuration settings can disable DTD processing or cap entity expansion in XML parsers.
Input validation can enforce limits on XML entity expansion and recursion depth before parsing occurs.
Least-functionality configuration can prohibit unsafe DTD features or external entity resolution.
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 introduction of improper recursive entity handling in XML code.
Hardened configuration baselines can disable or limit DTD entity expansion in XML parsers.
Identifying and recording vulnerabilities can discover XML entity expansion flaws before exploitation.
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 can detect and block XML entity-expansion vulnerabilities before deployment.
Secure SDLC mandates input validation and parser hardening that can prevent unbounded entity expansion.
Application security requirements can explicitly call for limits on XML entity recursion and DTD processing.
Secure architecture principles discourage unsafe parser configurations that enable entity expansion attacks.
Secure coding standards directly require disabling or restricting recursive entity references in XML parsers.