# CVE-2026-32597: PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation) > PyJWT fails to reject tokens with unknown critical extensions, allowing attackers to bypass security checks intended by the token issuer. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 12 Mar 2026 - **Updated:** 10 Sep 2026 - **Also known as:** AZL-93030, BELL-CVE-2026-32597, CLEANSTART-2026-AJ13963, CLEANSTART-2026-TW81518, CLSA-2026-1775608265, CLSA-2026-1786522025, CLSA-2026-1787028607, DEBIAN-CVE-2026-32597, ECHO-b1a0-3286-88da, GHSA-752w-5fwx-jx9f, MINI-232x-3rgh-cj3x, MINI-26w8-mvh8-vhgg, MINI-49hw-ffpr-7x6x, MINI-623r-4pvp-jcqh, MINI-6p3c-x5xj-r52g, MINI-6x62-67m6-h74x, MINI-82mv-5q32-wx4j, MINI-84m4-mx65-mwmx, MINI-8cf4-6696-9rfg, MINI-94wx-mv79-h9w6, MINI-cc4j-xxwr-vqhp, MINI-chfc-28gq-m5c4, MINI-g7qr-f579-xpgq, MINI-gg5h-4798-8643, MINI-hm7q-3gmr-2h4q, MINI-hmgq-mh3r-vjj6, MINI-qqh2-qmc4-cc9f, MINI-rjjg-hrq7-wfcx, OESA-2026-3117, PYSEC-2026-120, ROOT-APP-PYPI-CVE-2026-32597, SUSE-SU-2026:1199-1, SUSE-SU-2026:1389-1, SUSE-SU-2026:1400-1, SUSE-SU-2026:20839-1, SUSE-SU-2026:20869-1, SUSE-SU-2026:20934-1, UBUNTU-CVE-2026-32597, USN-8133-1, openSUSE-SU-2026:10397-1, openSUSE-SU-2026:10681-1, openSUSE-SU-2026:20431-1 ## What is CVE-2026-32597? CVE-2026-32597 is a high-severity vulnerability in jpadilla pyjwt, published on 12 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description 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. Weakness: CWE-863 (Incorrect Authorization), CWE-347 (Improper Verification of Cryptographic Signature), CWE-345 (Insufficient Verification of Data Authenticity) ## Which versions are affected by CVE-2026-32597? 3 open source packages ship an affected version, including pyjwt and PyJWT. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `pyjwt` | PyPI | All versions | 2.12.0 | | `pyjwt` | PyPI | All versions | 2.12.0 | | `PyJWT` | PyPI | All versions | 2.12.0 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Micro 5.5 | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Module for Basesystem 15 SP7 | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Module for Public Cloud 12 | All versions | 1.5.3-3.19.1 | | `python-PyJWT` | SUSE:Linux Enterprise Module for Public Cloud 15 SP4 | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Module for Python 3 15 SP7 | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server 15 SP4-LTSS | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server 15 SP4-LTSS | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server 15 SP5-LTSS | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server 15 SP5-LTSS | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server 15 SP6-LTSS | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server 15 SP6-LTSS | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server 16.0 | All versions | 2.12.1-160000.1.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | All versions | 2.4.0-150200.3.11.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | SUSE:Linux Enterprise Server for SAP applications 16.0 | All versions | 2.12.1-160000.1.1 | | `python-PyJWT` | SUSE:Linux Micro 6.0 | All versions | 2.9.0-2.1 | | `python-PyJWT` | SUSE:Linux Micro 6.2 | All versions | 2.12.1-160000.1.1 | | `python-PyJWT` | openSUSE:Leap 15.6 | All versions | 2.8.0-150400.8.10.1 | | `python-PyJWT` | openSUSE:Leap 16.0 | All versions | 2.12.1-160000.1.1 | | `python-PyJWT` | openSUSE:Tumbleweed | All versions | 2.12.1-1.1 | | `python-social-auth-core` | openSUSE:Tumbleweed | All versions | 4.8.7-1.1 | Products: Pyjwt Project Pyjwt. ## How do I fix CVE-2026-32597? Upgrade pyjwt to 2.12.0 or later. ## Is CVE-2026-32597 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32597 exists. ## Other vulnerabilities in jpadilla pyjwt - [CVE-2026-102268](https://insights.sbomify.com/CVE-2026-102268/): PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard (critical 9.1) - [CVE-2026-102266](https://insights.sbomify.com/CVE-2026-102266/): PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation (high 7.4) - [CVE-2026-102267](https://insights.sbomify.com/CVE-2026-102267/): PyJWT: PyJWKClient follows redirects when fetching JWKS (high 7.4) - [CVE-2026-102271](https://insights.sbomify.com/CVE-2026-102271/): PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard (high 7.4) - [CVE-2026-102272](https://insights.sbomify.com/CVE-2026-102272/): PyJWT BOM Bypass (high 7.4) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-32597 and fix it if it is affected. What it is: CVE-2026-32597 is a high-severity vulnerability in jpadilla pyjwt, published on 12 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32597 exists. Affected packages and fixed versions: - pyjwt (PyPI): affected all versions; fixed in 2.12.0 - pyjwt (PyPI): affected all versions; fixed in 2.12.0 - PyJWT (PyPI): affected all versions; fixed in 2.12.0 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-32597/ (Markdown: https://insights.sbomify.com/CVE-2026-32597/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-32597 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-32597 - OSV: https://osv.dev/vulnerability/CVE-2026-32597 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-32597/ Summaries are generated and may contain mistakes; the official description above is the record.