CVE-2026-18739

LOWPre-NVD 2.52.5—
EchelonGraph scoreMEDIUM 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 — 4 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: 0.1%CVSS: 2.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
2.5LOWmedium confidence
EG Risk
11
EG Risk 11/100CISA SSVC

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%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
2nd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 4, 2026

Last Modified

August 31, 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.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatpopt-main-1.19-11.1.hum12026-08-19redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
popt1.18-2, 1.18-3, 1.19+dfsg-1, 1.19+dfsg-1~exp1, 1.19+dfsg-2
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
popt1.19+dfsg-1, 1.19+dfsg-2
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
popt1.19+dfsg-2
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
popt1.19+dfsg-2
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 47× 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.

Showing the most recent 100 of 133 total refreshes for this CVE.

  1. 2026-10-04 23:21 UTCEPSS rescore
  2. 2026-10-04 06:15 UTCEG score recompute
  3. 2026-10-04 06:15 UTCVendor advisory
  4. 2026-10-04 06:15 UTCGHSA enrichment
  5. 2026-10-01 19:49 UTCEPSS rescore
  6. 2026-10-01 02:29 UTCEG score recompute
  7. 2026-10-01 02:29 UTCVendor advisory
  8. 2026-10-01 02:29 UTCGHSA enrichment
  9. 2026-09-30 15:02 UTCEPSS rescore
  10. 2026-09-29 15:20 UTCEPSS rescore
  11. 2026-09-28 13:51 UTCEPSS rescore
  12. 2026-09-28 02:47 UTCEG score recompute
  13. 2026-09-28 02:47 UTCVendor advisory
  14. 2026-09-28 02:47 UTCGHSA enrichment
  15. 2026-09-27 13:47 UTCEPSS rescore
  16. 2026-09-26 15:58 UTCEPSS rescore
  17. 2026-09-25 04:44 UTCEG score recompute
  18. 2026-09-25 04:44 UTCVendor advisory
  19. 2026-09-25 04:44 UTCGHSA enrichment
  20. 2026-09-22 03:34 UTCEG score recompute
  21. 2026-09-22 03:34 UTCVendor advisory
  22. 2026-09-22 03:34 UTCGHSA enrichment
  23. 2026-09-18 19:27 UTCEPSS rescore
  24. 2026-09-18 03:44 UTCEG score recompute
  25. 2026-09-18 03:44 UTCVendor advisory
Show 75 more
  1. 2026-09-18 03:44 UTCGHSA enrichment
  2. 2026-09-16 14:07 UTCEPSS rescore
  3. 2026-09-16 05:14 UTCEPSS rescore
  4. 2026-09-15 06:59 UTCEG score recompute
  5. 2026-09-15 06:59 UTCVendor advisory
  6. 2026-09-15 06:59 UTCGHSA enrichment
  7. 2026-09-13 16:46 UTCEPSS rescore
  8. 2026-09-12 07:59 UTCEG score recompute
  9. 2026-09-12 07:59 UTCVendor advisory
  10. 2026-09-12 07:59 UTCGHSA enrichment
  11. 2026-09-11 14:52 UTCEPSS rescore
  12. 2026-09-11 09:36 UTCEPSS rescore
  13. 2026-09-10 09:34 UTCEPSS rescore
  14. 2026-09-09 11:02 UTCEG score recompute
  15. 2026-09-09 11:02 UTCVendor advisory
  16. 2026-09-09 11:02 UTCGHSA enrichment
  17. 2026-09-08 22:00 UTCEPSS rescore
  18. 2026-09-07 16:01 UTCEPSS rescore
  19. 2026-09-06 14:17 UTCEG score recompute
  20. 2026-09-06 14:17 UTCVendor advisory
  21. 2026-09-06 14:17 UTCGHSA enrichment
  22. 2026-09-06 13:47 UTCEPSS rescore
  23. 2026-09-04 05:06 UTCEPSS rescore
  24. 2026-09-03 17:33 UTCEG score recompute
  25. 2026-09-03 17:33 UTCVendor advisory
  26. 2026-09-03 17:32 UTCGHSA enrichment
  27. 2026-09-01 13:53 UTCEPSS rescore
  28. 2026-08-31 18:36 UTCEG score recompute
  29. 2026-08-31 18:36 UTCVendor advisory
  30. 2026-08-31 18:35 UTCGHSA enrichment
  31. 2026-08-31 17:31 UTCVendor advisory
  32. 2026-08-31 17:31 UTCGHSA enrichment
  33. 2026-08-31 16:40 UTCVendor advisory
  34. 2026-08-31 16:40 UTCGHSA enrichment
  35. 2026-08-31 15:39 UTCEG score recompute
  36. 2026-08-31 15:39 UTCVendor advisory
  37. 2026-08-31 15:39 UTCGHSA enrichment
  38. 2026-08-30 19:17 UTCEPSS rescore
  39. 2026-08-30 05:13 UTCEG score recompute
  40. 2026-08-30 05:13 UTCVendor advisory
  41. 2026-08-30 05:13 UTCGHSA enrichment
  42. 2026-08-30 01:22 UTCEPSS rescore
  43. 2026-08-28 21:41 UTCEPSS rescore
  44. 2026-08-27 14:25 UTCEPSS rescore
  45. 2026-08-27 08:28 UTCEG score recompute
  46. 2026-08-27 08:28 UTCVendor advisory
  47. 2026-08-27 08:28 UTCGHSA enrichment
  48. 2026-08-26 14:46 UTCEPSS rescore
  49. 2026-08-24 10:06 UTCEG score recompute
  50. 2026-08-24 10:06 UTCVendor advisory
  51. 2026-08-24 10:06 UTCGHSA enrichment
  52. 2026-08-21 13:21 UTCEG score recompute
  53. 2026-08-21 13:21 UTCVendor advisory
  54. 2026-08-21 13:21 UTCGHSA enrichment
  55. 2026-08-21 13:09 UTCEG score recompute
  56. 2026-08-21 13:09 UTCVendor advisory
  57. 2026-08-21 13:09 UTCGHSA enrichment
  58. 2026-08-20 22:55 UTCEPSS rescore
  59. 2026-08-19 17:03 UTCEPSS rescore
  60. 2026-08-19 14:34 UTCEG score recompute
  61. 2026-08-19 14:34 UTCGHSA enrichment
  62. 2026-08-19 13:40 UTCEG score recompute
  63. 2026-08-19 13:40 UTCGHSA enrichment
  64. 2026-08-18 13:48 UTCEPSS rescore
  65. 2026-08-18 03:39 UTCEG score recompute
  66. 2026-08-18 03:39 UTCGHSA enrichment
  67. 2026-08-17 13:47 UTCEPSS rescore
  68. 2026-08-16 14:56 UTCEPSS rescore
  69. 2026-08-16 02:14 UTCEPSS rescore
  70. 2026-08-15 06:55 UTCEG score recompute
  71. 2026-08-15 06:55 UTCGHSA enrichment
  72. 2026-08-15 01:30 UTCEPSS rescore
  73. 2026-08-13 22:00 UTCEPSS rescore
  74. 2026-08-12 09:19 UTCEG score recompute
  75. 2026-08-12 09:19 UTCGHSA enrichment

Related CVEs(same product + same vendor + same CWE)

Same product

2 shown

Debian:11:popt · Debian:12:popt

Same vendor

1 shown

redhat:RHSA-2026:56984

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 on August 4, 2026, with the most recent update on August 31, 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 0.1% probability of exploitation in the next 30 days (2nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-18739?
CVE-2026-18739 has a CVSS base score of 2.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-18739?
A fix for CVE-2026-18739 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-18739 are linked in the Vendor Advisories panel on this page.

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