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CVE-2026-102273— PyJWT accepts public JWK containers as HMAC secrets

Quick assessment

Affected
jpadilla pyjwt
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

PyJWT 是 JSON Web Token（JWT）标准的 Python 实现。在版本 2.13.0 至 2.14.0 期间，PyJWT 的 方法存在安全漏洞。该问题源于 HMAC 密钥保护机制仅能识别顶层公开 JSON Web Key（JWK）格式，而无法正确处理容器化的 JWK 表示形式。当应用程序同时支持 HMAC 和不对称算法，并将公开 JWK 容器作为原始密钥传入时，就会触发此漏洞。其后果是：公开的不对称密钥材料被错误地接受为 HMAC 共享密钥。因此，攻击者若知晓该公钥，便可伪造包含任意已认证声明的令

CVSS 7.4 · High
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I. Basic Information for CVE-2026-102273

Vulnerability Information
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Vulnerability Title
PyJWT accepts public JWK containers as HMAC secrets
Source: CVE Program / CVE List V5
Vulnerability Description
PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because HMAC key guard only recognizes top-level public JWK forms and misses container representations. This occurs when an application allows HMAC and asymmetric algorithms and passes a public JWK container as the raw key. As a result, public asymmetric key material is accepted as the HMAC secret. Consequently, an attacker who knows the public key can forge a token with arbitrary authenticated claims. This issue is fixed in version 2.14.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
密码学签名的验证不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
jpadilla pyjwt >= 2.13.0, < 2.14.0 -

II. Public POCs for CVE-2026-102273

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III. Intelligence Information for CVE-2026-102273

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Other References for CVE-2026-102273 (3)

Same Patch Batch · jpadilla · 2026-09-28 · 13 CVEs total

CVE-2026-102268 9.1 CRITICAL PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip th
CVE-2026-102266 7.4 HIGH PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation
CVE-2026-102267 7.4 HIGH PyJWT: PyJWKClient follows redirects when fetching JWKS
CVE-2026-102271 7.4 HIGH PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217
CVE-2026-102272 7.4 HIGH PyJWT BOM Bypass
CVE-2026-102275 6.5 MEDIUM PyJWT accepts inconsistent OKP x/d JWKs, causing public/private key identity confusion
CVE-2026-102274 5.9 MEDIUM PyJWT: Malformed RSA JWK aborts parsing of an entire JWK Set
CVE-2026-101918 5.3 MEDIUM PyJWT: Unauthenticated RecursionError DoS in pre-verification payload parse (PyJWKClient.g
CVE-2026-101917 5.3 MEDIUM PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (inc
CVE-2026-102265 5.3 MEDIUM PyJWT: Uncaught RecursionError in jwt.decode() on deeply nested token header
CVE-2026-102269 4.8 MEDIUM PyJWT: Non-canonical signature segments enable raw-token revocation bypass
CVE-2026-102270 4.4 MEDIUM PyJWT: ReDoS vulnerability when calling the `is_pem_format` function.

IV. Related Vulnerabilities

Same product: pyjwt
Same vendor: jpadilla
Same weakness: CWE-347

V. Comments for CVE-2026-102273

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