CVE-2025-30204 | jwt-go allows excessive memory allocation during header parsing

golang-jwt is a Go implementation of JSON Web Tokens. Starting in version 3.2.0 and prior to versions 5.2.2 and 4.5.2, the function parse.ParseUnverified splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request whose Authorization header consists of Bearer followed by many period characters, a call to that function incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. This issue is fixed in 5.2.2 and 4.5.2.

Published: 2025-03-21 Last update: 2026-04-15 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-30204 is rated Low Risk (36.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.06%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-30204

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-24 0.04% 0.06% +0.02%
2 2025-11-21 0.24% 0.04% -0.19%
3 2025-11-18 0.24%

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-30204

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]

Weakness enumeration for CVE-2025-30204

GitHub Security Advisory for CVE-2025-30204

GHSA-mh63-6h87-95cp · Severity: high · Ecosystem: go — jwt-go allows excessive memory allocation during header parsing

OS Trackers for CVE-2025-30204

vendor priority summary link
alpine high CVE-2025-30204: 1 source package rows (rclone); 2 state rows across 2 repos (3.22-community, edge-community); fixed 2, open 0. https://security.alpinelinux.org/vuln/CVE-2025-30204
debian not yet assigned CVE-2025-30204 not yet assigned priority: Debian including 2 source packages (golang-github-golang-jwt-jwt, golang-github-golang-jwt-jwt-v5), 7 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 6, open 1. https://security-tracker.debian.org/tracker/CVE-2025-30204
redhat high https://access.redhat.com/security/cve/CVE-2025-30204
suse high CVE-2025-30204 severity important: SUSE including 193 source package names (13.2-9.11:libexpat1-2.7.1-slfo.1.1_3.1, 13.2-9.11:libsolv-tools-base-0.7.34-1.1, …), 664 product×package rows across 83 product lines (Container containers/milvus, Container suse/sl-micro/6.0/baremetal-os-container, … (83 product lines)): Known Not Affected 369, Fixed 289, First Fixed 6. https://www.suse.com/security/cve/CVE-2025-30204/
ubuntu medium CVE-2025-30204 medium priority: Ubuntu including 2 source packages (golang-github-golang-jwt-jwt, golang-github-golang-jwt-jwt-v5), 14 status rows across 7 suites (focal, jammy, noble, oracular, plucky, questing, upstream): not-affected 4, DNE 3, needs-triage 3, ignored 2, released 2. https://ubuntu.com/security/CVE-2025-30204

Affected software / configurations for CVE-2025-30204

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-30204

cvelogic Threat Intelligence