How severe is CVE-2026-3099?

CVE-2026-3099 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-3099 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-3099?

CVE-2026-3099 primarily affects Redhat Enterprise Linux. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-3099?

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

Does CVE-2026-3099 have an EU (EUVD) identifier?

Yes. CVE-2026-3099 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11573.

When was CVE-2026-3099 published?

CVE-2026-3099 was published on 2026-03-12 and last updated on 2026-06-17.

CVE-2026-3099

CVE-2026-3099 is a medium-severity vulnerability in Redhat Enterprise Linux with a CVSS 3.x base score of 5.8. 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-323.

Key facts

Severity: Medium (CVSS 3.x base score 5.8)
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-11573
Weakness: CWE-323
Affected product: Redhat Enterprise Linux
Published: 2026-03-12
Last modified: 2026-06-17

Description

A flaw was found in Libsoup. The server-side digest authentication implementation in the SoupAuthDomainDigest class does not properly track issued nonces or enforce the required incrementing nonce-count (nc) attribute. This vulnerability allows a remote attacker to capture a single valid authentication header and replay it repeatedly. Consequently, the attacker can bypass authentication and gain unauthorized access to protected resources, impersonating the legitimate user.

Frequently asked questions

What is CVE-2026-3099?: A flaw was found in Libsoup. The server-side digest authentication implementation in the SoupAuthDomainDigest class does not properly track issued nonces or enforce the required incrementing nonce-count (nc) attribute. This vulnerability allows a remote attacker to capture a single valid authentication header and replay it repeatedly. Consequently, the attacker can bypass authentication and gain unauthorized access to protected resources, impersonating the legitimate user.
How severe is CVE-2026-3099?: CVE-2026-3099 has a CVSS 3.x base score of 5.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-3099 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-3099?: CVE-2026-3099 primarily affects Redhat Enterprise Linux. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-3099?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-3099 have an EU (EUVD) identifier?: Yes. CVE-2026-3099 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11573.
When was CVE-2026-3099 published?: CVE-2026-3099 was published on 2026-03-12 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:gnome:libsoup:-:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*

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