CVE-2026-63091

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-20. A secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-45961 (ENISA EUVD) · GHSA-gqm5-f386-9r92 (GitHub Security Advisories)Source: ENISA EUVD

6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 6.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's SCP size-record parser that allows authenticated low-privilege attackers to bypass ASLR by sending a crafted file size value of UINT64_MAX, which results in a negative off_t value. Attackers can exploit the subsequent conversion to uint32_t, causing an approximately 4 GB requested read length and forcing the server to read beyond the end of the SSH channel data and write overread process memory into the uploaded file. In tested configurations, the disclosed data contains libc, libcrypto, and PIE pointers sufficient to derive their randomized base addresses, thereby bypassing ASLR and enabling reliable exploitation of memory corruption vulnerabilities in the same process.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
44th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 20, 2026

Last Modified

July 30, 2026

Advisory Details (6)

Auto-updated Jul 20, 2026
Patch available. Sources: github_commit, github_pr, github_release.
Web page

ProFTPD mod_sftp Signed Integer Overflow via SCP Size-Record Parser | Advisories | VulnCheck

https://www.vulncheck.com/advisories/proftpd-mod-sftp-signed-integer-overflow-via-scp-size-record-parser
GitHub release Patch Available

v1.3.9c

Patch available: proftpd/proftpd v1.3.9c

https://github.com/proftpd/proftpd/releases/tag/v1.3.9c
GitHub release Patch Available

v1.3.10rc3

Patch available: proftpd/proftpd v1.3.10rc3-3 (pre-release)

https://github.com/proftpd/proftpd/releases/tag/v1.3.10rc3-3
GitHub pull request Patch Available

Exercise caution when reading the client-provided file size for SCP u…

Patch available: proftpd/proftpd v1.3.10rc3-3 (PR #2201 merged 2026-07-01)

https://github.com/proftpd/proftpd/pull/2201
GitHub commit Patch Available

commit b9b7dde1bcd7 (proftpd/proftpd)

Patch available: proftpd/proftpd v1.3.10rc3-3 (contains commit b9b7dde1bcd7)

https://github.com/proftpd/proftpd/commit/b9b7dde1bcd74bc23366484d53856b67b8d6d95e
Web page

proftpd/RELEASE_NOTES at master · proftpd/proftpd · GitHub

https://github.com/proftpd/proftpd/blob/master/RELEASE_NOTES

Vendor Advisories for CVE-2026-63091(1)

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 rangeFix by version rangeDependents
proftpd-dfsg1.3.7a+dfsg-12 ... 1.3.9~dfsg-5 (36 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
proftpd-dfsg1.3.8+dfsg-4 ... 1.3.9~dfsg-5 (28 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
proftpd-dfsg1.3.8.c+dfsg-4, 1.3.8.c+dfsg-4+deb13u1, 1.3.8.c+dfsg-4+deb13u2
  • every version up to 1.3.8.c+dfsg-4+deb13u3: fixed in 1.3.8.c+dfsg-4+deb13u3
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
proftpd-dfsg1.3.8.c+dfsg-4 ... 1.3.9~dfsg-5 (8 versions)
  • every version up to 1.3.9c~dfsg-1: fixed in 1.3.9c~dfsg-1
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 43× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 196 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 96 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  2. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  3. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  4. 2026-10-25 14:13 UTCEG score recompute
  5. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  6. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  7. 2026-10-22 19:51 UTCEG score recompute
  8. 2026-10-22 19:50 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  9. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  10. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  11. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-10-18 03:23 UTCEG score recompute
  15. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  16. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  17. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  18. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  19. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  20. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  21. 2026-10-12 15:49 UTCEG score recompute
  22. 2026-10-11 19:33 UTCEG score recompute
  23. 2026-10-11 16:48 UTCEG score recompute
  24. 2026-10-11 14:10 UTCEG score recompute
  25. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
Show 75 more
  1. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  2. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  3. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  4. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  5. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  6. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  7. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  8. 2026-10-04 14:57 UTCEG score recompute
  9. 2026-10-04 14:57 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  10. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  11. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  12. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  13. 2026-10-01 07:45 UTCEG score recompute
  14. 2026-10-01 07:45 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  15. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  16. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  17. 2026-09-28 06:23 UTCEG score recompute
  18. 2026-09-28 06:23 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  19. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  20. 2026-09-24 04:11 UTCEG score recompute
  21. 2026-09-24 04:11 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  22. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  23. 2026-09-23 01:43 UTCEG score recompute
  24. 2026-09-23 01:43 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  25. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  26. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  27. 2026-09-18 03:58 UTCEG score recompute
  28. 2026-09-18 03:58 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  29. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  30. 2026-09-16 12:48 UTCEG score recompute
  31. 2026-09-16 12:48 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  32. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  33. 2026-09-13 14:35 UTCEG score recompute
  34. 2026-09-13 14:35 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  35. 2026-09-12 12:34 UTCEG score recompute
  36. 2026-09-12 12:34 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  37. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  38. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  39. 2026-09-11 09:29 UTCEG score recompute
  40. 2026-09-11 09:29 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  41. 2026-09-09 11:58 UTCEG score recompute
  42. 2026-09-09 11:58 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  43. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  44. 2026-09-07 22:56 UTCEG score recompute
  45. 2026-09-07 22:56 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  46. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  47. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  48. 2026-09-06 11:46 UTCEG score recompute
  49. 2026-09-06 11:46 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  50. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  51. 2026-09-05 09:35 UTCEG score recompute
  52. 2026-09-05 09:35 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  53. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  54. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  55. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  56. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  57. 2026-08-31 04:39 UTCEG score recompute
  58. 2026-08-31 04:39 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  59. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  60. 2026-08-30 02:37 UTCEG score recompute
  61. 2026-08-30 02:37 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  62. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  63. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  64. 2026-08-28 01:41 UTCEG score recompute
  65. 2026-08-28 01:41 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  66. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  67. 2026-08-26 23:02 UTCEG score recompute
  68. 2026-08-26 23:02 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  69. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  70. 2026-08-25 21:00 UTCEG score recompute
  71. 2026-08-25 21:00 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  72. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  73. 2026-08-24 18:59 UTCEG score recompute
  74. 2026-08-24 18:58 UTCGHSA enrichmentGHSA-gqm5-f386-9r92 · GitHub severity HIGH · GitHub CVSS 6.5
  75. 2026-08-23 14:58 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-63091?
CVE-2026-63091 is a medium-severity vulnerability; its CVE record was published on July 20, 2026. ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the modsftp module's SCP size-record parser that allows authenticated low-privilege attackers to bypass ASLR by sending a crafted file size value of UINT64MAX, which results in a negative offt value. Attackers…
When was CVE-2026-63091 made public?
CVE-2026-63091 was made public on July 1, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on July 20, 2026. EchelonGraph's copy of the record carries a last-modified date of July 30, 2026; the record at its source may have been updated since.
Is CVE-2026-63091 actively exploited?
CVE-2026-63091 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (44th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-63091?
CVE-2026-63091 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-63091?
A fix for CVE-2026-63091 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-63091 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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