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Vulnerabilities

Vulnerability · CVE-2026-27932

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards.

Published Mar 3, 2026 · catalog updated Jun 17, 2026 · joserfc is a Python

Check if you run it

No confirmed exploitation is on record for CVE-2026-27932. EPSS is 0.35%. Act only if a listed version of joserfc is a Python is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (joserfc is a Python).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.35%
Remediation
Version ranges on file
Affected products
cpe hsiaoming/joserfc · stated joserfc

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (DoS) via CPU exhaustion. When the library decrypts a JSON Web Encryption (JWE) token using Password-Based Encryption (PBES2) algorithms, it reads the p2c (PBES2 Count) parameter directly from the token's protected header. This parameter defines the number of iterations for the PBKDF2 key derivation function. Because joserfc does not validate or bound this value, an attacker can specify an extremely large iteration count (e.g., 2^31 - 1), forcing the server to expend massive CPU resources processing a single token. This vulnerability exists at the JWA layer and impacts all high-level JWE and JWT decryption interfaces if PBES2 algorithms are allowed by the application's policy.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe hsiaoming/joserfcversion unspecified
  • stated joserfc<= 1.6.2

How to fix CVE-2026-27932

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27932. EPSS is 0.35%. Act only if a listed version of joserfc is a Python is installed.

Which versions are affected?

Compare what you have installed with <= 1.6.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 3, 2026 · NIST NVD

    Detected

    joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (DoS) via CPU exhaustion. When the library decrypts a JSON Web Encryption (JWE) token using Password-Based Encryption (PBES2) algorithms, it re

  2. Jun 17, 2026 · NIST NVD

    Updated

    joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (DoS) via CPU exhaustion. When the library decrypts a JSON Web Encryption (JWE) token using Password-Based Encryption (PBES2) algorithms, it re

Sources

  • CVE.orgVulnerability recordCVE-2026-27932

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27932

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-27932

    joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (DoS) via CPU exhaustio

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.