Red Hat Enterprise Linux 10: Reusing a Nonce, Key Pair in Encryption
CVE-2026-3099 is a high-severity reusing a nonce, key pair in encryption vulnerability in Red Hat Enterprise Linux 10 from Red Hat, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Red Hat Enterprise Linux 10 you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| GNOME | Libsoup | Not specified in the record | Not stated |
| Red Hat | Enterprise Linux | 6.0; 7.0; 8.0; 9.0; 10.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.8 | Medium | CNA (redhat.com) |
| CVSS 3.1 | 7.3 | High | NVD |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reusing a Nonce, Key Pair in Encryption
Nonces should be used for the present occasion and only once.
How developers prevent this class of flaw
- Use techniques such as requiring incrementing, time based and/or challenge response to assure uniqueness of nonces.
More Reusing a Nonce, Key Pair in Encryption vulnerabilities (CWE-323)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- access.redhat.com/security/cve/CVE-2026-3099Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2442232Issue Tracking, Third Party Advisory
Technical write-ups (may include proof of concept)
- gitlab.gnome.org/GNOME/libsoup/-/issues/495Exploit, Issue Tracking, Third Party Advisory
Other vulnerabilities in Red Hat Enterprise Linux 10
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.3 High severity
- 7.5 High severity
Recent Reusing a Nonce, Key Pair in Encryption vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 9.1 Critical severity
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