CVE-2026-18739

LOWPre-NVD 2.52.5—
EchelonGraph scoreHIGH confidence

Score 2.5 from GitHub Security Advisory (severity: LOW) published 2026-08-04. a secondary CVSS source baseline 2.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
2.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 2.5Exploit: None knownExposed: 0

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

A flaw was found in popt, a command-line option parsing library. An off-by-one error in the poptStuffArgs function, when repeatedly called by a host application or through deep alias nesting, can lead to corruption of internal program data. This corruption could potentially enable a local attacker to execute arbitrary code if the host application then unsafely processes the altered data.

CVSS v3
2.5
EG Score
2.5(high)
EG Risk
11(Track)
EG Risk 11/100SSVC: 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
Severity25% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

August 4, 2026

Last Modified

August 19, 2026

References (3)

Vendor Advisories for CVE-2026-18739(3)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
popt1.18-2, 1.18-3, 1.19+dfsg-1, 1.19+dfsg-1~exp1, 1.19+dfsg-2——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
popt1.19+dfsg-1, 1.19+dfsg-2——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
popt1.19+dfsg-2——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
popt1.19+dfsg-2——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 50× 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. 2026-08-19 17:03 UTCEPSS rescore
  2. 2026-08-19 14:34 UTCEG score recompute
  3. 2026-08-19 14:34 UTCGHSA enrichment
  4. 2026-08-19 13:40 UTCEG score recompute
  5. 2026-08-19 13:40 UTCGHSA enrichment
  6. 2026-08-18 13:48 UTCEPSS rescore
  7. 2026-08-18 03:39 UTCEG score recompute
  8. 2026-08-18 03:39 UTCGHSA enrichment
  9. 2026-08-17 13:47 UTCEPSS rescore
  10. 2026-08-16 14:56 UTCEPSS rescore
  11. 2026-08-16 02:14 UTCEPSS rescore
  12. 2026-08-15 06:55 UTCEG score recompute
  13. 2026-08-15 06:55 UTCGHSA enrichment
  14. 2026-08-15 01:30 UTCEPSS rescore
  15. 2026-08-13 22:00 UTCEPSS rescore
  16. 2026-08-12 09:19 UTCEG score recompute
  17. 2026-08-12 09:19 UTCGHSA enrichment
  18. 2026-08-11 13:42 UTCEPSS rescore
  19. 2026-08-11 00:00 UTCEPSS rescore
  20. 2026-08-09 13:46 UTCEPSS rescore
  21. 2026-08-09 12:35 UTCEG score recompute
  22. 2026-08-09 12:35 UTCGHSA enrichment
  23. 2026-08-08 16:37 UTCEPSS rescore
  24. 2026-08-06 15:50 UTCEG score recompute
  25. 2026-08-06 15:50 UTCGHSA enrichment
Show 25 more
  1. 2026-08-06 13:46 UTCEPSS rescore
  2. 2026-08-05 22:18 UTCEG score recompute
  3. 2026-08-05 22:18 UTCGHSA enrichment
  4. 2026-08-05 22:05 UTCEG score recompute
  5. 2026-08-05 22:05 UTCGHSA enrichment
  6. 2026-08-05 19:17 UTCEPSS rescore
  7. 2026-08-05 19:01 UTCEG score recompute
  8. 2026-08-05 19:01 UTCGHSA enrichment
  9. 2026-08-05 05:26 UTCEG score recompute
  10. 2026-08-05 05:25 UTCGHSA enrichment
  11. 2026-08-05 04:36 UTCEG score recompute
  12. 2026-08-05 04:36 UTCGHSA enrichment
  13. 2026-08-05 00:20 UTCGHSA enrichment
  14. 2026-08-04 23:18 UTCEG score recompute
  15. 2026-08-04 23:18 UTCGHSA enrichment
  16. 2026-08-04 22:56 UTCEG score recompute
  17. 2026-08-04 22:56 UTCGHSA enrichment
  18. 2026-08-04 15:10 UTCEPSS rescore
  19. 2026-08-04 14:18 UTCEG score recompute
  20. 2026-08-04 14:18 UTCGHSA enrichment
  21. 2026-08-04 13:59 UTCEG score recompute
  22. 2026-08-04 13:59 UTCGHSA enrichment
  23. 2026-08-04 06:30 UTCEG score recompute
  24. 2026-08-04 05:38 UTCEG score recompute
  25. 2026-08-04 05:38 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-18739?
CVE-2026-18739 is a low vulnerability published on August 4, 2026. A flaw was found in popt, a command-line option parsing library. An off-by-one error in the poptStuffArgs function, when repeatedly called by a host application or through deep alias nesting, can lead to corruption of internal program data. This corruption could potentially enable a local attacker…
When was CVE-2026-18739 disclosed?
CVE-2026-18739 was first published in the National Vulnerability Database on August 4, 2026, with the most recent update on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18739 actively exploited?
CVE-2026-18739 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 99.3% of all scored CVEs.
What is the CVSS score of CVE-2026-18739?
CVE-2026-18739 has a CVSS v3 base score of 2.5 (NVD).
How do I remediate CVE-2026-18739?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18739, 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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