CVE-2026-62381

MEDIUMPre-NVD 6.66.6—
EchelonGraph scoreHIGH confidence

Score 6.6 from GitHub Security Advisory published 2026-08-22. a secondary CVSS source baseline 6.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
6.6EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.6Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

luci-lib-px5g (LuCI) contains a heap-based buffer overflow in the native ASN.1 encoding routine asn1_add_obj (x509write.c) when signing a certificate with a 2040-bit RSA key. For a 255-byte signature, the BIT STRING allocation is computed from the DER length encoding of 255 bytes, but the payload written after prepending the unused-bits byte is 256 bytes, requiring one additional DER length octet. As a result the allocation is 259 bytes while the tag, length, unused-bits byte, and signature require 260 bytes, and the final memcpy writes one byte beyond the heap buffer. The overflow is reachable through the exported Lua interface via create_selfsigned(); whether it is remotely exploitable depends on the embedding application. The vulnerable code is present on the openwrt-18.06 through openwrt-25.12 release branches and is absent from master, where the luci-lib-px5g package has been removed rather than patched.

CVSS v3
6.6
EG Score
6.6(high)
EG Risk
46(Track)
EG Risk 46/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity66% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
0%
KEV
Not listed

Published

August 22, 2026

Last Modified

August 24, 2026

Advisory Details (2)

Auto-updated Aug 22, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

luci-lib-px5g 2040-bit Certificate Signing Heap Buffer Overflow | Advisories | VulnCheck

https://www.vulncheck.com/advisories/luci-lib-px5g-2040-bit-certificate-signing-heap-buffer-overflow
github Patch Available🟡 PoC Available

2040-bit certificate signing causes a heap buffer overflow in `luci-lib-px5g` · Advisory · openwrt/luci · GitHub

https://github.com/openwrt/luci/security/advisories/GHSA-jgc3-4q3p-g6xh

Vendor Advisories for CVE-2026-62381(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 17× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-29 19:24 UTCEG score recompute
  2. 2026-08-29 19:23 UTCGHSA enrichment
  3. 2026-08-28 21:42 UTCEPSS rescore
  4. 2026-08-28 19:32 UTCGHSA enrichment
  5. 2026-08-27 19:44 UTCGHSA enrichment
  6. 2026-08-26 19:58 UTCGHSA enrichment
  7. 2026-08-25 20:12 UTCEG score recompute
  8. 2026-08-25 20:12 UTCGHSA enrichment
  9. 2026-08-25 13:49 UTCEPSS rescore
  10. 2026-08-24 20:27 UTCEG score recompute
  11. 2026-08-24 20:27 UTCGHSA enrichment
  12. 2026-08-24 20:02 UTCEG score recompute
  13. 2026-08-24 20:02 UTCGHSA enrichment
  14. 2026-08-24 12:56 UTCEG score recompute
  15. 2026-08-24 12:56 UTCGHSA enrichment
  16. 2026-08-23 13:10 UTCEG score recompute
  17. 2026-08-23 13:10 UTCGHSA enrichment
  18. 2026-08-22 13:21 UTCEG score recompute
  19. 2026-08-22 12:46 UTCEG score recompute
  20. 2026-08-22 12:45 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-62381?
CVE-2026-62381 is a medium vulnerability published on August 22, 2026. luci-lib-px5g (LuCI) contains a heap-based buffer overflow in the native ASN.1 encoding routine asn1addobj (x509write.c) when signing a certificate with a 2040-bit RSA key. For a 255-byte signature, the BIT STRING allocation is computed from the DER length encoding of 255 bytes, but the payload…
When was CVE-2026-62381 disclosed?
CVE-2026-62381 was first published in the National Vulnerability Database on August 22, 2026, with the most recent update on August 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-62381 actively exploited?
CVE-2026-62381 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 99.9% of all scored CVEs.
What is the CVSS score of CVE-2026-62381?
CVE-2026-62381 has a CVSS v3 base score of 6.6 (NVD).
How do I remediate CVE-2026-62381?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-62381, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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