Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NSummary
CVE-2026-32597 is a high-severity Insufficient Verification of Data Authenticity (CWE-345) vulnerability in Pyjwt Project Pyjwt. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); ranked at the 19th 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 AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — 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.
CVE-2026-32597 affects PyJWT, a Python implementation of JSON Web Tokens (JWTs), in versions prior to 2.12.0. The vulnerability stems from the library's failure to properly validate the "crit" (Critical) Header Parameter as defined in RFC 7515 §4.1.11. Specifically, when a JSON Web Signature (JWS) token includes a "crit" array listing extensions that PyJWT does not recognize, the library accepts the token rather than rejecting it, violating the RFC's MUST requirement. This issue is tracked under CWE-345 (Insufficient Verification of Data Authenticity) and CWE-863 (Incorrect Authorization), with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).
A remote, unauthenticated attacker can exploit this vulnerability by crafting a malicious JWS token that includes unrecognized "crit" header extensions. Any application relying on vulnerable PyJWT for token validation could then accept these invalid tokens, potentially enabling integrity violations such as bypassing authentication or authorization checks if the token is used in a security-critical context.
The PyJWT GitHub security advisory (GHSA-752w-5fwx-jx9f) confirms the issue and states that it is fixed in version 2.12.0, recommending that users upgrade to this or later versions to mitigate the vulnerability. No workarounds are detailed in the provided references.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-11728
Vulnerability Data
PyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that PyJWT does not…
more
understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC. This vulnerability is fixed in 2.12.0.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
—
—
- 27 hardening rules · 5 OS baselines
V3.5.5
Mitigating Controls (NIST 800-53 r5) AI
AC-3 directly requires correct enforcement of authorization decisions on every access request, structurally preventing incorrect checks.
Explicit requirement to protect session authenticity structurally prevents the weakness for communications.
AC-24 ensures access-control decisions are made and applied consistently, reducing the chance of an incorrect authorization result.
A reference monitor that is always invoked and tamper-proof forces every authorization decision through a verified, correct path.
Requiring cryptographic protection mechanisms forces correct signature verification to be implemented for data protection.
Integrity verification tools detect (but do not stop) the acceptance of data lacking authenticity.
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.
Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.
Digital signatures are explicitly cited to protect integrity of data-at-rest, so proper verification directly mitigates the weakness.
Digital signatures are explicitly cited to protect integrity of data-in-transit, so proper verification directly mitigates the weakness.
CWE-345 directly impairs RC.RP-05's verification of restored-asset integrity/authenticity, largely defeating the outcome while still leaving other restoration-confirmation steps partially viable.
Requires assessing authenticity and integrity of acquired assets, which commonly relies on signature verification but is limited to pre-acquisition.
Secure SDLC practices include code signing and signature verification requirements, addressing the weakness during development.
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 missing or weak data authenticity verification.
Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.
Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.
Network controls can enforce authenticated channels, reducing risk of accepting unauthentic data.
Secure network services often include authenticity checks for data exchanged over those services.
Cryptographic mechanisms directly verify data origin and integrity, preventing acceptance of unauthentic data.
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 (4 rules)
- V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-345, CWE-347
- V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345, CWE-347
- V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-863
Oracle Linux 9 (2 rules)
- V-271525 OL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-345, CWE-347
- V-271523 OL 9 must check the GPG signature of locally installed software packages before installation. prevents CWE-347
RHEL 7 (3 rules)
- V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345, CWE-347
- V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345, CWE-347
- V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-863
RHEL 8 (3 rules)
- V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345, CWE-347
- V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-345
- V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863
RHEL 9 (1 rule)
- V-257822 RHEL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-345, CWE-347