CVE-2026-55738

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-06-17. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 8.8Exploit: NoneExposed: 0

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

A stack-based buffer overflow exists in the raw_to_header() function in src/microtar.c in rxi microtar 0.1.0. The function copies the 100-byte name and linkname fields of a TAR header with strcpy() without guaranteeing null termination of the source. The POSIX ustar format permits these fixed-width fields to be fully populated with non-null bytes, so a crafted archive whose linkname field (followed by the trailing padding of the 512-byte raw header) contains no null terminator causes strcpy() to read past the end of the 512-byte raw header stack buffer and to write past the destination header buffer. A remote attacker who supplies a crafted TAR archive that the victim opens or parses (via mtar_open(), mtar_read_header(), or mtar_find()) can cause an out-of-bounds read and a stack buffer overflow, resulting in denial of service (crash) and potentially arbitrary code execution. Confirmed with AddressSanitizer: stack-buffer-overflow READ of size 356 in raw_to_header at src/microtar.c:112.

CVSS v3
8.8
EG Score
8.8(high)
EPSS
46.7%
KEV
Not listed

Published

June 17, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Jun 18, 2026
No patch confirmed yet.
generic
https://raw.githubusercontent.com/rxi/microtar/master/src/microtar.c
generic

microtar/src/microtar.c at master · rxi/microtar · GitHub

https://github.com/rxi/microtar/blob/master/src/microtar.c#L111
generic

GitHub - rxi/microtar: A lightweight tar library written in ANSI C · GitHub

https://github.com/rxi/microtar

Vendor Advisories for CVE-2026-55738(1)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 91× 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 113 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-55738?
CVE-2026-55738 is a high vulnerability published on June 17, 2026. A stack-based buffer overflow exists in the rawtoheader() function in src/microtar.c in rxi microtar 0.1.0. The function copies the 100-byte name and linkname fields of a TAR header with strcpy() without guaranteeing null termination of the source. The POSIX ustar format permits these fixed-width…
When was CVE-2026-55738 disclosed?
CVE-2026-55738 was first published in the National Vulnerability Database on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55738 actively exploited?
CVE-2026-55738 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 46.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55738?
CVE-2026-55738 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-55738?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55738, 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.

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