CVE-2026-23991 | go-tuf affected by client DoS via malformed server response

go-tuf is a Go implementation of The Update Framework (TUF). Starting in version 2.0.0 and prior to version 2.3.1, if the TUF repository (or any of its mirrors) returns invalid TUF metadata JSON (valid JSON but not well formed TUF metadata), the client will panic during parsing, causing a denial of service. The panic happens before any signature is validated. This means that a compromised repository/mirror/cache can DoS clients without having access to any signing key. Version 2.3.1 fixes the issue. No known workarounds are available.

Published: 2026-01-22 Last update: 2026-02-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-23991 is rated Low Risk (24.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.01%). 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-2026-23991

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 2026-01-22 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23991

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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.
 2.2 3.6 [email protected]
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-2026-23991

GitHub Security Advisory for CVE-2026-23991

GHSA-846p-jg2w-w324 · Severity: medium · Ecosystem: go — go-tuf affected by client DoS via malformed server response

OS Trackers for CVE-2026-23991

vendor priority summary link
debian not yet assigned CVE-2026-23991 not yet assigned priority: Debian including 1 source packages (golang-github-theupdateframework-go-tuf), 3 status rows across 3 suites (forky, sid, trixie): resolved 2, open 1. https://security-tracker.debian.org/tracker/CVE-2026-23991
redhat medium — https://access.redhat.com/security/cve/CVE-2026-23991
suse medium CVE-2026-23991 severity moderate: SUSE including 13 source package names (cosign-3.0.5-1.1, cosign-3.0.5-150400.3.35.1, …), 49 product×package rows across 38 product lines (Image SL-Micro, Image SL-Micro-Azure, … (38 product lines)): Fixed 46, Known Not Affected 2, First Fixed 1. https://www.suse.com/security/cve/CVE-2026-23991/
ubuntu medium CVE-2026-23991 medium priority: Ubuntu including 1 source packages (golang-github-theupdateframework-go-tuf), 4 status rows across 4 suites (jammy, noble, questing, upstream): needs-triage 3, DNE 1. https://ubuntu.com/security/CVE-2026-23991

Affected software / configurations for CVE-2026-23991

Vendor Product Version Raw CPE
theupdateframework go-tuf >= 2.0.0, < 2.3.1 cpe:2.3:a:theupdateframework:go-tuf:*:*:*:*:*:*:*:*

References for CVE-2026-23991

cvelogic Threat Intelligence