# CVE-2026-103001: PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse

> Attackers can bypass JWT claim verification by exploiting mutable options dictionary reuse in PyJWT, allowing acceptance of invalid tokens.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/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:** 30 Sep 2026
- **Updated:** 5 Oct 2026
- **Also known as:** AZL-105642, BELL-CVE-2026-103001, CLEANSTART-2026-AF59744, CLEANSTART-2026-CW76652, DEBIAN-CVE-2026-103001, ECHO-8665-d21f-1204, GHSA-gvp8-978c-rx2q, MINI-2c7m-qv8f-mcfv, MINI-2wwg-x4c5-26xv, MINI-3ggg-p56x-wcjx, MINI-4c43-pgjv-h2h3, MINI-57xc-mqqm-4phg, MINI-6ccv-g2rm-mj94, MINI-7f5x-22j4-m93c, MINI-c5vf-3c2m-vpwc, MINI-f463-842q-gj7v, MINI-f5r6-7prx-45j8, MINI-fmrw-r96r-2q9h, MINI-gqhg-q8v3-h2fc, MINI-h5g5-pgx3-8j9h, MINI-hcmq-p6q3-v8cj, MINI-hvwp-5xp7-m53v, MINI-mr3w-24jp-9gqg, MINI-p8xc-cx6h-fr42, MINI-r5wq-8hjw-jxj2, MINI-rwmm-f6pr-5p65, MINI-w678-3jhm-cc5f, MINI-w9fp-v4vh-7v9v, MINI-wqxq-q76c-f8vq, PYSEC-2026-4146, UBUNTU-CVE-2026-103001

## What is CVE-2026-103001?

CVE-2026-103001 is a medium-severity vulnerability in jpadilla pyjwt, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

PyJWT is a Python implementation of JSON Web Token standards. From 2.11.0 through 2.13.0, PyJWT's PyJWT._merge_options() method can modify a caller-supplied mutable options mapping when verify_signature is false. If an application reuses that same mapping for a later decode() or decode_complete() call and changes verify_signature to true, the mapping can retain false values for expiration, not-before, issued-at, audience, issuer, subject, and JWT ID checks. A signed token with invalid registered claims can then be accepted without disabling signature verification, but applications that create a fresh options mapping for each call are not affected.

Weakness: CWE-471 (Modification of Assumed-Immutable Data (MAID))

## Which versions are affected by CVE-2026-103001?

3 open source packages ship an affected version, including pyjwt and PyJWT. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pyjwt` | PyPI | From 2.11.0 to 2.13.0 | None |
| `pyjwt` | PyPI | From 2.11.0 to 2.13.0 | None |
| `PyJWT` | PyPI | From 2.11.0 to 2.13.0 | None |

Products: Pyjwt Project Pyjwt.

## How do I fix CVE-2026-103001?

Upgrade to a fixed version.

## Is CVE-2026-103001 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103001 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-2026-32597](https://insights.sbomify.com/CVE-2026-32597/): PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation) (high 7.5)
- [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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103001 and fix it if it is affected.

What it is: CVE-2026-103001 is a medium-severity vulnerability in jpadilla pyjwt, published on 30 Sep 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-2026-103001 exists.

Affected packages and fixed versions:
- pyjwt (PyPI): affected from 2.11.0 up to 2.13.0; no fix listed
- pyjwt (PyPI): affected from 2.11.0 up to 2.13.0; no fix listed
- PyJWT (PyPI): affected from 2.11.0 up to 2.13.0; no fix listed

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-2026-103001/ (Markdown: https://insights.sbomify.com/CVE-2026-103001/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103001
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103001
- OSV: https://osv.dev/vulnerability/CVE-2026-103001

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103001/
Summaries are generated and may contain mistakes; the official description above is the record.