What is the CVSS score of CVE-2026-27932?

CVE-2026-27932 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.1%.

Is there a public PoC exploit available for CVE-2026-27932?

Yes, a public proof-of-concept exploit is available for CVE-2026-27932. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2026-27932?

Within 24 hours: Identify all systems and applications using joserfc library and document their criticality and internet exposure. Within 7 days: Apply available vendor patch to all affected systems, prioritizing internet-facing and production environments. Within 30 days: Complete patching of all remaining systems including development and test environments, and implement monitoring for suspicious CPU consumption patterns.

Joserfc CVE-2026-27932

HIGH

Allocation of Resources Without Limits or Throttling (CWE-770)

2026-03-03 security-advisories@github.com

GHSA-w5r5-m38g-f9f9

Denial Of Service Python Joserfc Suse

7.5

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Craft malicious JWE token with high p2c value
Exploit

Send token to joserfc for decryption
Execution

PBKDF2 executes excessive iterations
Impact

CPU exhaustion causes DoS

Vulnerability Assessment

Weakness	CWE CWE-770 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V2 - Validation and Business Logic Resource allocation limits MITRE ATT&CK 1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	No special conditions — remote unauthenticated exploitation against joserfc versions 1.6.2 and earlier when processing JWE tokens with PBES2 algorithms. Attacker must send crafted token to application endpoint that decrypts JWE tokens.
Impact	CVSS 7.5 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required. Public exploit/POC available.
Exploit ScenarioDerived	An attacker without authentication could exploit this vulnerability to compromise the affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Joserfc versions 1.6.2 and earlier fail to validate the PBES2 iteration count parameter in JWE tokens, allowing unauthenticated attackers to trigger CPU exhaustion by specifying arbitrarily large values in the p2c header field. An attacker can exploit this resource exhaustion vulnerability to cause denial of service against any system using the library to decrypt JWE tokens. Public exploit code exists for this vulnerability, and a patch is available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 22:05 CVSS 7.5

RemediationAI

A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.

Affected Packages

pypi joserfc fix: 1.6.3

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in pypi

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-770 (Allocation of Resources Without Limits or Throttling). Affects 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 defin

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SUSE HIGH

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

PoC Detected

Mar 05, 2026 - 18:00 vuln.today

Public exploit code

Patch released

Mar 05, 2026 - 18:00 nvd

Patch available

CVE Published

Mar 03, 2026 - 23:15 nvd

HIGH 7.5

DescriptionGitHub Advisory

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.

Executive ViewAI

Why It Matters

A resource exhaustion vulnerability in the joserfc Python library (CVE-2026-27932) allows unauthenticated attackers to trigger CPU exhaustion and deny service to affected applications. Any organization using joserfc 1.6.2 or earlier in production environments is at immediate risk of service disruption without immediate patching.

Business Impact: High

Compensating Controls

Apply vendor patch. If immediate patching is not feasible, implement rate limiting and request throttling at the application or WAF layer to mitigate DoS attempts, disable JOSE functionality if not required, and segment affected services behind authentication and IP-based access controls.

Threat Intelligence Overview

EPSS Score

0.1%

Top 71% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS Vendor

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC Yes

EPSS 0.1%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.