How severe is CVE-2026-23991?

CVE-2026-23991 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-23991 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23991?

CVE-2026-23991 affects Theupdateframework Go-tuf. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-23991?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-23991 have an EU (EUVD) identifier?

Yes. CVE-2026-23991 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3673.

When was CVE-2026-23991 published?

CVE-2026-23991 was published on 2026-01-22 and last updated on 2026-06-17.

CVE-2026-23991

CVE-2026-23991 is a medium-severity vulnerability in Theupdateframework Go-tuf with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-617.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-3673
Weakness: CWE-617
Affected product: Theupdateframework Go-tuf
Published: 2026-01-22
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-23991?: 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.
How severe is CVE-2026-23991?: CVE-2026-23991 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-23991 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23991?: CVE-2026-23991 affects Theupdateframework Go-tuf. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-23991?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-23991 have an EU (EUVD) identifier?: Yes. CVE-2026-23991 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3673.
When was CVE-2026-23991 published?: CVE-2026-23991 was published on 2026-01-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:theupdateframework:go-tuf:*:*:*:*:*:*:*:*

More vulnerabilities in Theupdateframework Go-tuf

CVE-2022-29173 — High (CVSS 8.0): go-tuf is a Go implementation of The Update Framework (TUF). go-tuf does not correctly implement the client workflow…
CVE-2026-23992 — Medium (CVSS 5.9): go-tuf is a Go implementation of The Update Framework (TUF). Starting in version 2.0.0 and prior to version 2.3.1, a…
CVE-2026-24686 — Medium (CVSS 4.7): go-tuf is a Go implementation of The Update Framework (TUF). go-tuf's TAP 4 Multirepo Client uses the map file…

All CVEs affecting Theupdateframework Go-tuf →

Other CWE-617 (Reachable Assertion) vulnerabilities

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CVE-2019-9795 — Critical (CVSS 9.8): A vulnerability where type-confusion in the IonMonkey just-in-time (JIT) compiler could potentially be used by…
CVE-2026-31739 — High (CVSS 8.8): In the Linux kernel, the following vulnerability has been resolved: crypto: tegra - Add missing CRYPTO_ALG_ASYNC The…
CVE-2020-12417 — High (CVSS 8.8): Due to confusion about ValueTags on JavaScript Objects, an object may pass through the type barrier, resulting in…
CVE-2020-6623 — High (CVSS 8.8): stb stb_truetype.h through 1.22 has an assertion failure in stbtt__cff_get_index.
CVE-2020-6619 — High (CVSS 8.8): stb stb_truetype.h through 1.22 has an assertion failure in stbtt__buf_seek.

Browse all CWE-617 (Reachable Assertion) vulnerabilities →