CVE-2026-29785
CVE-2026-29785 is a high-severity vulnerability in Linuxfoundation Nats-server with a CVSS 3.x base score of 7.5. 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-476.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 1% (47th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-15963
- Weakness: CWE-476
- Affected product: Linuxfoundation Nats-server
- Published:
- Last modified:
Description
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.14 and 2.12.5, if the nats-server has the "leafnode" configuration enabled (not default), then anyone who can connect can crash the nats-server by triggering a panic. This happens pre-authentication and requires that compression be enabled (which it is, by default, when leafnodes are used). Versions 2.11.14 and 2.12.5 contain a fix. As a workaround, disable compression on the leafnode port.
Frequently asked questions
- What is CVE-2026-29785?
- NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.14 and 2.12.5, if the nats-server has the "leafnode" configuration enabled (not default), then anyone who can connect can crash the nats-server by triggering a panic. This happens pre-authentication and requires that compression be enabled (which it is, by default, when leafnodes are used). Versions 2.11.14 and 2.12.5 contain a fix. As a workaround, disable compression on the leafnode port.
- How severe is CVE-2026-29785?
- CVE-2026-29785 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-29785 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-29785?
- CVE-2026-29785 affects Linuxfoundation Nats-server. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-29785?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-29785 have an EU (EUVD) identifier?
- Yes. CVE-2026-29785 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-15963.
- When was CVE-2026-29785 published?
- CVE-2026-29785 was published on 2026-03-25 and last updated on 2026-06-30.
References
- https://advisories.nats.io/CVE/secnote-2026-04.txt
- https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8
- https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6
- https://access.redhat.com/errata/RHSA-2026:21769
- https://access.redhat.com/errata/RHSA-2026:22347
- https://access.redhat.com/errata/RHSA-2026:23345
- https://access.redhat.com/security/cve/CVE-2026-29785
- https://bugzilla.redhat.com/show_bug.cgi?id=2451444
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29785.json
Affected products (1)
- cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*
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