CVE-2025-4877

MEDIUMPre-NVD 4.54.5—
EchelonGraph scoreMEDIUM confidence

Score 4.5 from GitHub Security Advisory published 2025-08-20. a secondary CVSS source baseline 4.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
4.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.5Exploit: None knownExposed: 0

A fix is available — apply it.

There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large input buffer to ssh_get_fingerprint_hash() function. In such cases the bin_to_base64() function can experience an integer overflow leading to a memory under allocation, when that happens it's possible that the program perform out of bounds write leading to a heap corruption. This issue affects only 32-bits builds of libssh.

CVSS v3
4.5
EG Score
4.5(medium)
EG Risk
20(Track)
EG Risk 20/100SSVC: 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
Severity45% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

August 20, 2025

Last Modified

August 31, 2026

Advisory Details (5)

Auto-updated Jun 27, 2026
Patch available. Sources: redhat.
generic
https://www.libssh.org/security/advisories/CVE-2025-4877.txt
generic

projects/libssh.git - libssh shared repository

https://git.libssh.org/projects/libssh.git/commit/?h=stable-0.11&id=6fd9cc8ce3958092a1aae11f1f2e911b2747732d
redhat Patch Available

2376193 – (CVE-2025-4877) CVE-2025-4877 libssh: Write beyond bounds in binary to base64 conversion functions

Affected: Red Hat Enterprise Linux 9

https://bugzilla.redhat.com/show_bug.cgi?id=2376193
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2025-4877
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:18683

Vendor Advisories for CVE-2025-4877(2)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibssh-gcrypt-dev (0.6.3-4.3ubuntu0.6+esm2) @ xenial2026-08-31ubuntu
ubuntulibssh-doc (0.11.1-1ubuntu0.1) @ plucky2026-08-31ubuntu
redhatlibssh-0:0.10.4-18.el92026-05-19redhat

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 rangeFixed inDependents
libssh0.9.5-1 ... 0.9.8-0+deb11u1 (6 versions)0.9.8-0+deb11u2—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libssh0.10.5-2, 0.10.5-3, 0.10.5-3+hurd.1, 0.10.6-0+deb12u10.10.6-0+deb12u2—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libssh—0.11.2-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libssh—0.11.2-1—

Weakness Classification(1)

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

Additional Vendor Advisories

(3)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 41× 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 201 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2025-4877?
CVE-2025-4877 is a medium vulnerability published on August 20, 2025. There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large input buffer to sshgetfingerprinthash() function. In such cases the binto_base64() function can experience an integer overflow leading to a memory under allocation, when that happens it's…
When was CVE-2025-4877 disclosed?
CVE-2025-4877 was first published in the National Vulnerability Database on August 20, 2025, 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-2025-4877 actively exploited?
CVE-2025-4877 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 90.3% of all scored CVEs.
What is the CVSS score of CVE-2025-4877?
CVE-2025-4877 has a CVSS v3 base score of 4.5 (NVD).
How do I remediate CVE-2025-4877?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-4877, 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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