CVE-2026-31931 | Suricata tls: null dereference in tls.alpn rule keyword

Suricata is a network IDS, IPS and NSM engine. From version 8.0.0 to before version 8.0.4, use of the "tls.alpn" rule keyword can cause Suricata to crash with a NULL dereference. This issue has been patched in version 8.0.4.

Published: 2026-04-02 Last update: 2026-04-07 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-31931 is rated Low Risk (32.1/100): CVSS High severity, with low exploitation likelihood (EPSS 0.02%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-31931

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-22 0.06% 0.02% -0.04%
2 2026-04-08 0.05% 0.06% +0.01%
3 2026-04-03 — 0.05% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-31931

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-31931

OS Trackers for CVE-2026-31931

vendor priority summary link
alpine — CVE-2026-31931: 1 source package rows (suricata); 4 state rows across 2 repos (3.23-community, edge-community); fixed 0, open 4. https://security.alpinelinux.org/vuln/CVE-2026-31931
debian unimportant CVE-2026-31931 unimportant priority: Debian including 1 source packages (suricata), 4 status rows across 4 suites (bullseye, forky, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2026-31931
redhat high — https://access.redhat.com/security/cve/CVE-2026-31931
ubuntu medium CVE-2026-31931 medium priority: Ubuntu including 1 source packages (suricata), 6 status rows across 6 suites (bionic, jammy, noble, questing, upstream, xenial): needs-triage 6. https://ubuntu.com/security/CVE-2026-31931

Affected software / configurations for CVE-2026-31931

Vendor Product Version Raw CPE
oisf suricata >= 8.0.0, < 8.0.4 cpe:2.3:a:oisf:suricata:*:*:*:*:*:*:*:*

References for CVE-2026-31931

cvelogic Threat Intelligence