Vulnerability in PyJWT (CVE-2026-102275)
Summary
Vulnerability in PyJWT (CVE-2026-102275). Data can be tampered with by attackers. Exploitable via cnf.jkt. Mitigation: upgrade to 2.15.0 or later.
Original description
The description as published by the source.
Summary
PyJWT accepts internally inconsistent OKP private JWKs where the declared public key x does not correspond to the supplied private key d.
When d is present, OKPAlgorithm.from_jwk() constructs the Ed25519/Ed448 private key from d without verifying that the public key derived from d matches x. As a result, the original JWK can contain one public key identity while PyJWT performs cryptographic operations using a different key.
In affected DPoP integrations, this can allow a stolen sender-constrained access token to be used without possession of the legitimate holder's private key.
Details
The vulnerable logic is in jwt/algorithms.py:
if "x" not in obj:
raise InvalidKeyError('OKP should have "x" parameter')
x = base64url_decode(obj.get("x"))
if "d" not in obj:
if curve == "Ed25519":
return Ed25519PublicKey.from_public_bytes(x)
return Ed448PublicKey.from_public_bytes(x)
d = base64url_decode(obj.get("d"))
if curve == "Ed25519":
return Ed25519PrivateKey.from_private_bytes(d)
return Ed448PrivateKey.from_private_bytes(d)
When d is present, x is parsed but never compared with the public key derived from d.
For example, PyJWT accepts:
{
"kty": "OKP",
"crv": "Ed25519",
"x": "",
"d": ""
}
even though x and d belong to different key pairs.
The behavior has existed since OKP private-JWK import was introduced:
- Ed25519: PyJWT 2.1.0+
- Ed448: PyJWT 2.2.0+
- Confirmed through P…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-102275 has been found in PyJWT.
Attackers can target a specific entry point like cnf.jkt over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 6.5/10.
What to do: upgrade PyJWT to 2.15.0 or later.
If unsure, ask your IT team or search "PyJWT CVE-2026-102275" on the vendor's site.
CVE-2026-102275 (PyJWT) — CWE-345 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: cnf.jkt / master / patched_versions / InvalidKeyError
Patched: 2.15.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-345) exists in PyJWT. Attackers reach the vulnerable code path via cnf.jkt without authentication.
Check the vendor advisory for the affected versions of PyJWT. Attack surface: cnf.jkt / master / patched_versions / InvalidKeyError.
Severity: Medium (CVSS 6.5/10). Data can be tampered with by attackers.
Update to 2.15.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'PyJWT' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'PyJWT' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
PyJWTを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade PyJWT to 2.15.0ステージング環境で 2.15.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com