CVE-2026-78161 — warmcat libwebsockets LECP CBOR Recording lecp.c report_raw_cbor out-of-bounds write
A vulnerability was found in warmcat libwebsockets 4.5.0. Impacted is the function report_raw_cbor of the file lib/misc/lecp.c of the component LECP CBOR Recording. The manipulation results in out-of-bounds write. The attack can be launched remotely. The exploit has been made public and could be used. The patch is identified as 1d44554a1bb262db63ff4e240152a9deecd99054. It is best practice to apply a patch to resolve this issue.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.4% (30-day exploitation probability)+5
- Technical severity (high)+6
- CISA SSVC: exploitation "poc"+5
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Warmcat Libwebsockets).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Warmcat | Libwebsockets | version 4.5.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 6.9 | CVSS 4.0 | Medium | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
| 5.5 | CVSS 4.0 | Medium | — | — | cna@vuldb.com via NIST National Vulnerability Database |
| 7.3 | CVSS 3.1 | High | 3.9 | 3.4 | cna@vuldb.com via NIST National Vulnerability Database |
| 7.3 | CVSS 3.1 | High | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
| 7.3 | CVSS 3.0 | High | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
| 7.5 | CVSS 2.0 | High | 10.0 | 6.4 | cna@vuldb.com via NIST National Vulnerability Database |
| 7.5 | CVSS 2.0 | High | — | — | VulDB via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L (score shown at the top: cna@vuldb.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CWE-119 · Buffer Errors (Improper Restriction of Operations within Memory Bounds)
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.41%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · warmcat/libwebsockets
- SSVC assessment updated
- Record published
- CVSS changed · 7.3
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
8 on the record
- github.com/warmcat/libwebsockets/commit/1d44554a1bb262db63ff4e240152a9deecd99054
- github.com/warmcat/libwebsockets/
- vuldb.com/vuln/394543/cti
- vuldb.com/vuln/394543
- vuldb.com/cve/CVE-2026-78161
- github.com/biniamf/pocs/tree/main/libwebsockets-lecp-lecp_parse-cbor_pos_oob_wri
- github.com/biniamf/pocs/blob/main/libwebsockets-lecp-lecp_parse-cbor_pos_oob_wri
- vuldb.com/submit/883225
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-10650 warmcat libwebsockets SSH Protocol sshd.c lws_ssh_parse_plaintext resource consumption Jun 2, 2026
- Medium CVE-2025-11680 Out-of-bounds Write in libwebsockets PNG parsing Oct 20, 2025
- Medium CVE-2025-11679 Out-of-bounds Read in libwebsockets PNG parsing Oct 20, 2025
- Medium CVE-2025-11677 Use After Free in libwebsockets WebSocket server Oct 20, 2025
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No fixed version, patch or mitigation documented.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-78161 is "warmcat libwebsockets LECP CBOR Recording lecp.c report_raw_cbor out-of-bounds write", rated High. It affects Libwebsockets (Warmcat); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.3 describes technical severity. EPSS 0.41% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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