CVE-2026-32597 | PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

Exp

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 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.

Published: 2026-03-13 Last update: 2026-05-05 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-32597 is rated Exploit Available (50/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-32597

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-32597

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-13 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-32597

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-32597

GitHub Security Advisory for CVE-2026-32597

GHSA-752w-5fwx-jx9f · Severity: high · Ecosystem: pip — PyJWT accepts unknown `crit` header extensions

OS Trackers for CVE-2026-32597

vendor priority summary link
debian not yet assigned CVE-2026-32597 not yet assigned priority: Debian including 1 source packages (pyjwt), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-32597
redhat high — https://access.redhat.com/security/cve/CVE-2026-32597
suse high CVE-2026-32597 severity important: SUSE including 255 source package names (2.1.3-7.50:grub2-2.12~rc1-7.1, 2.1.3-7.50:grub2-i386-pc-2.12~rc1-7.1, …), 338 product×package rows across 39 product lines (Container suse/sl-micro/6.0/baremetal-os-container, Container suse/sl-micro/6.0/base-os-container, … (39 product lines)): Known Affected 231, Fixed 88, First Fixed 19. https://www.suse.com/security/cve/CVE-2026-32597/
ubuntu medium CVE-2026-32597 medium priority: Ubuntu including 1 source packages (pyjwt), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, upstream, xenial): released 6, needs-triage 1. https://ubuntu.com/security/CVE-2026-32597

Affected software / configurations for CVE-2026-32597

Vendor Product Version Raw CPE
pyjwt_project pyjwt < 2.12.0 cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:*

References for CVE-2026-32597

cvelogic Threat Intelligence