CVE-2026-18238

MEDIUMPre-NVD 5.05.0—
EchelonGraph scoreHIGH confidence

Score 5.0 from GitHub Security Advisory published 2026-09-05. a secondary CVSS source baseline 5.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.0Exploit: None knownExposed: 0

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

The rpcap client code that processes a RPCAP_MSG_PACKET message received from the server incorrectly validates its headers. A malicious server can send a crafted message and cause the client to treat up to 20 bytes of the client process memory beyond the end of the buffer as if it was a part of the captured packet.

CVSS v3
5.0
EG Score
5.0(high)
EG Risk
23(Track)
EG Risk 23/100SSVC: 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
Severity50% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

September 5, 2026

Last Modified

September 8, 2026

Advisory Details (1)

Auto-updated Sep 5, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
github_commit

commit b9590d482986 (the-tcpdump-group/libpcap)

Fix landed in the-tcpdump-group/libpcap commit b9590d482986 — awaiting tagged release

https://github.com/the-tcpdump-group/libpcap/commit/b9590d482986d64673712460aae1d48d11fa0473

Vendor Advisories for CVE-2026-18238(2)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libpcap1.10.3-1 ... 1.10.6-2 (13 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libpcap1.10.5-2, 1.10.6-1, 1.10.6-2——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libpcap1.10.5-2, 1.10.6-1, 1.10.6-2——

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 25× in last 7d / 52× 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. 2026-09-19 06:56 UTCEG score recompute
  2. 2026-09-19 06:56 UTCVendor advisory
  3. 2026-09-19 06:56 UTCGHSA enrichment
  4. 2026-09-18 19:27 UTCEPSS rescore
  5. 2026-09-18 06:06 UTCEG score recompute
  6. 2026-09-18 06:06 UTCVendor advisory
  7. 2026-09-18 06:06 UTCGHSA enrichment
  8. 2026-09-17 05:17 UTCEG score recompute
  9. 2026-09-17 05:17 UTCVendor advisory
  10. 2026-09-17 05:17 UTCGHSA enrichment
  11. 2026-09-16 14:07 UTCEPSS rescore
  12. 2026-09-16 05:14 UTCEPSS rescore
  13. 2026-09-16 04:28 UTCVendor advisory
  14. 2026-09-16 04:28 UTCGHSA enrichment
  15. 2026-09-15 03:27 UTCEG score recompute
  16. 2026-09-15 03:27 UTCVendor advisory
  17. 2026-09-15 03:27 UTCGHSA enrichment
  18. 2026-09-14 02:38 UTCEG score recompute
  19. 2026-09-14 02:38 UTCVendor advisory
  20. 2026-09-14 02:38 UTCGHSA enrichment
  21. 2026-09-13 16:46 UTCEPSS rescore
  22. 2026-09-13 01:49 UTCEG score recompute
  23. 2026-09-13 01:49 UTCVendor advisory
  24. 2026-09-13 01:49 UTCGHSA enrichment
  25. 2026-09-12 15:00 UTCEPSS rescore
Show 27 more
  1. 2026-09-12 00:59 UTCEG score recompute
  2. 2026-09-12 00:59 UTCVendor advisory
  3. 2026-09-12 00:59 UTCGHSA enrichment
  4. 2026-09-11 14:52 UTCEPSS rescore
  5. 2026-09-11 09:36 UTCEPSS rescore
  6. 2026-09-11 00:10 UTCEG score recompute
  7. 2026-09-11 00:09 UTCGHSA enrichment
  8. 2026-09-10 09:34 UTCEPSS rescore
  9. 2026-09-09 23:20 UTCEG score recompute
  10. 2026-09-09 23:20 UTCGHSA enrichment
  11. 2026-09-08 22:00 UTCEPSS rescore
  12. 2026-09-08 19:54 UTCGHSA enrichment
  13. 2026-09-08 17:00 UTCEG score recompute
  14. 2026-09-08 17:00 UTCVendor advisory
  15. 2026-09-08 17:00 UTCGHSA enrichment
  16. 2026-09-08 16:06 UTCEG score recompute
  17. 2026-09-08 16:06 UTCVendor advisory
  18. 2026-09-08 16:05 UTCGHSA enrichment
  19. 2026-09-07 21:03 UTCEG score recompute
  20. 2026-09-07 21:03 UTCGHSA enrichment
  21. 2026-09-07 16:01 UTCEPSS rescore
  22. 2026-09-06 20:14 UTCEG score recompute
  23. 2026-09-06 20:14 UTCGHSA enrichment
  24. 2026-09-06 13:47 UTCEPSS rescore
  25. 2026-09-05 19:24 UTCEG score recompute
  26. 2026-09-05 18:56 UTCEG score recompute
  27. 2026-09-05 18:55 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18238?
CVE-2026-18238 is a medium vulnerability published on September 5, 2026. The rpcap client code that processes a RPCAPMSGPACKET message received from the server incorrectly validates its headers. A malicious server can send a crafted message and cause the client to treat up to 20 bytes of the client process memory beyond the end of the buffer as if it was a part of the…
When was CVE-2026-18238 disclosed?
CVE-2026-18238 was first published in the National Vulnerability Database on September 5, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18238 actively exploited?
CVE-2026-18238 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 92.5% of all scored CVEs.
What is the CVSS score of CVE-2026-18238?
CVE-2026-18238 has a CVSS v3 base score of 5.0 (NVD).
How do I remediate CVE-2026-18238?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18238, 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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