CVE-2026-3099
MEDIUMDescription
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 to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L
Exploit Intelligence
Low risk: more likely to be exploited than 30% of all known CVEs.
References
Related Vulnerabilities
Other CWE-323 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2026-49952 | Critical | 9.1 | 4.7% | - | - |
| CVE-2017-13082 | High | 8.1 | 4.6% | - | Fix |
| CVE-2017-7902 | Critical | 9.8 | 2.6% | - | - |
| CVE-2017-13080 | Medium | 5.3 | 2.3% | - | Fix |
| CVE-2017-13084 | Medium | 6.8 | 2.2% | - | - |
| CVE-2017-13079 | Medium | 5.3 | 2.1% | - | Fix |
Common questions
How do I fix CVE-2026-3099?
Upgrade libsoup3 on debian unstable to 3.8.0-1 or later.
Is CVE-2026-3099 being actively exploited?
Not that we know of. CVE-2026-3099 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.36% is the estimated probability that it will be exploited in the next 30 days. That is higher than 30% of all scored CVEs.
How severe is CVE-2026-3099?
CVE-2026-3099 has a CVSS v3 base score of 5.8, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-3099 affect?
Published advisories record a fix for libsoup3 (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-23.