CVE-2017-6542

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-14. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekWeaponized
9.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • Public exploit code is available (Exploit-DB (verified), epss top5pct, public exploit)
CISA-KEV: Not listedEPSS PROB: 22%CVSS: 9.8Exploit: Exploit-DB (verified) · epss top5pct · public exploitExposed services: Not assessed

A fix is available — apply it.

The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an agent protocol message and leveraging the ability to connect to the Unix-domain socket representing the forwarded agent connection, which trigger a buffer overflow.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
75
EG Risk 75/100CISA 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
Severity98% × 45%
Exploitation65% × 40%
Automatability30% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
22%
EPSS %ILE
97th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (EG-KEV: weaponized) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). 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

March 27, 2017

Last Modified

June 17, 2026

Advisory Details (6)

Auto-updated Oct 5, 2026
🔬 Proof of concept available. Patch available.
generic🟡 PoC Available

PuTTY vulnerability vuln-agent-fwd-overflow

http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-agent-fwd-overflow.html
generic🟡 PoC Available

PuTTY < 0.68 - 'ssh_agent_channel_data' Integer Overflow Heap Corruption - Linux dos Exploit

https://www.exploit-db.com/exploits/42137/
generic

FileZilla: Buffer overflow (GLSA 201706-09) — Gentoo security

https://security.gentoo.org/glsa/201706-09
generic

PuTTY: Buffer overflow (GLSA 201703-03) — Gentoo security

https://security.gentoo.org/glsa/201703-03
generic

CVE-2017-6542 - PSIRT.COM

http://www.securityfocus.com/bid/97156
generic
http://www.securitytracker.com/id/1038067

Affected Packages

(8 across 8 ecosystems)
Alpine:v3.2(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.68-r0: fixed in 0.68-r0
—
Alpine:v3.3(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.68-r0: fixed in 0.68-r0
—
Alpine:v3.4(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.68-r0: fixed in 0.68-r0
—
Alpine:v3.5(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.68-r0: fixed in 0.68-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.67-3: fixed in 0.67-3
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.67-3: fixed in 0.67-3
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.67-3: fixed in 0.67-3
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
putty—
  • every version up to 0.67-3: fixed in 0.67-3
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 19× 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 152 total refreshes for this CVE.

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

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-42137✓ verified
    First seen Jun 7, 2017

    PuTTY < 0.68 - 'ssh_agent_channel_data' Integer Overflow Heap Corruption

    Open source ↗

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2017-6542?
CVE-2017-6542 is a critical vulnerability published on March 27, 2017. The sshagentchannel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an agent protocol message and leveraging the ability to connect to the Unix-domain socket representing the forwarded agent connection, which trigger a buffer…
When was CVE-2017-6542 disclosed?
CVE-2017-6542 was first published on March 27, 2017, with the most recent update 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-2017-6542 actively exploited?
CVE-2017-6542 is not currently on CISA's Known Exploited Vulnerabilities catalog. EchelonGraph's EG-KEV model classifies it as weaponized: a functional public exploit exists. FIRST EPSS estimates a 22% probability of exploitation in the next 30 days (97th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2017-6542?
CVE-2017-6542 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2017-6542?
A fix for CVE-2017-6542 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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