CVE-2026-53994

HIGHNVD 6.57.5
EchelonGraph scoreMEDIUM confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-18. NVD baseline CVSS 6.5; sources differ by 1.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week

Also known asEUVD-2026-45396 (ENISA EUVD) · GHSA-435f-wcrw-9x3x (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
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: 0.4%CVSS: 6.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

ProFTPD mod_sftp contains a heap-based buffer overflow reachable by an authenticated SFTP user. The fxp_packet_read() function accepts the attacker-supplied 32-bit big-endian SFTP packet length without a minimum sanity check. A value of 0 causes an unsigned subtraction elsewhere in the read path to underflow to approximately 4 GB. That oversized request reaches the core memory allocator, where the rounded size is computed in size_t but passed to new_block() as a 32-bit int; the low 32 bits of 0x100000000 are 0, so new_block() returns a small (~512-byte) block while the caller is told it received ~4 GB. The subsequent fill loop then streams attacker-controlled bytes past the end of the 544-byte allocation, producing an attacker-controlled heap buffer overflow. An authenticated user can crash the per-connection ProFTPD session child on demand with a single malformed SFTP packet (packet_len=0 followed by a body greater than approximately 544 bytes), producing reliable authenticated remote denial of service. Depending on heap layout and adjacent allocations, heap metadata corruption and further consequences beyond denial of service may be possible, though only denial of service is demonstrated by the supplied proof of concept.

CVSS v3
6.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 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 low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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
0.4%
EPSS %ILE
38th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS. 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 low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 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 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). 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)14 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 total (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 18, 2026

Last Modified

October 24, 2026

Advisory Details (3)

Auto-updated Jul 18, 2026
Patch available. Sources: github_commit.
Web page

ProFTPD mod_sftp Heap Buffer Overflow via Unsigned Integer Underflow and Size Truncation | Advisories | VulnCheck

https://www.vulncheck.com/advisories/proftpd-mod-sftp-heap-buffer-overflow-via-unsigned-integer-underflow-and-size-truncation
GitHub commit Patch Available

commit 7342836fa98e (proftpd/proftpd)

Patch available: proftpd/proftpd v1.3.9 (contains commit 7342836fa98e)

https://github.com/proftpd/proftpd/commit/7342836fa98e36209660a4c5805c801476f63936
Web page

GitHub - proftpd/proftpd: ProFTPD source code · GitHub

https://github.com/proftpd/proftpd

Vendor Advisories for CVE-2026-53994(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 (7 versions)
  • every version up to 1.3.9b~dfsg-1: fixed in 1.3.9b~dfsg-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 46× 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 237 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 137 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 0.4% · 38th percentile
  2. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  3. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 38th percentile
  4. 2026-10-25 14:20 UTCEG score recompute
  5. 2026-10-24 20:27 UTCEG score recompute
  6. 2026-10-24 20:27 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  7. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  8. 2026-10-24 01:14 UTCEG score recompute
  9. 2026-10-24 01:14 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  10. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  13. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  14. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  16. 2026-10-18 03:31 UTCEG score recompute
  17. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  18. 2026-10-17 08:09 UTCEG score recompute
  19. 2026-10-17 08:08 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  20. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  21. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  22. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  23. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  24. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  25. 2026-10-12 15:57 UTCEG score recompute
Show 75 more
  1. 2026-10-11 19:40 UTCEG score recompute
  2. 2026-10-11 16:55 UTCEG score recompute
  3. 2026-10-11 14:18 UTCEG score recompute
  4. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  7. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  8. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  9. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  10. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  11. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  12. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  13. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  14. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  15. 2026-10-01 10:22 UTCEG score recompute
  16. 2026-10-01 10:22 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  17. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  18. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  19. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  20. 2026-09-28 07:48 UTCEG score recompute
  21. 2026-09-28 07:48 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  22. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  23. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  24. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  25. 2026-09-24 04:27 UTCEG score recompute
  26. 2026-09-24 04:27 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  27. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  28. 2026-09-23 02:21 UTCEG score recompute
  29. 2026-09-23 02:21 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  30. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  31. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  32. 2026-09-18 04:29 UTCEG score recompute
  33. 2026-09-18 04:29 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  34. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  35. 2026-09-17 10:12 UTCEG score recompute
  36. 2026-09-17 10:12 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  37. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  38. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  39. 2026-09-14 06:08 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  40. 2026-09-13 17:25 UTCEG score recompute
  41. 2026-09-13 17:25 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  42. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  43. 2026-09-13 04:28 UTCEG score recompute
  44. 2026-09-13 04:28 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  45. 2026-09-12 10:27 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  46. 2026-09-11 21:03 UTCEG score recompute
  47. 2026-09-11 21:03 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  48. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  49. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  50. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  51. 2026-09-07 23:52 UTCEG score recompute
  52. 2026-09-07 23:52 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  53. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  54. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  55. 2026-09-06 13:19 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  56. 2026-09-05 20:24 UTCEG score recompute
  57. 2026-09-05 20:24 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  58. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  59. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  60. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  61. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  62. 2026-08-31 04:35 UTCEG score recompute
  63. 2026-08-31 04:35 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  64. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  65. 2026-08-30 15:52 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  66. 2026-08-30 03:09 UTCEG score recompute
  67. 2026-08-30 03:09 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  68. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  69. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  70. 2026-08-28 01:58 UTCEG score recompute
  71. 2026-08-28 01:58 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  72. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  73. 2026-08-27 13:15 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5
  74. 2026-08-27 00:31 UTCEG score recompute
  75. 2026-08-27 00:30 UTCGHSA enrichmentGHSA-435f-wcrw-9x3x · GitHub severity HIGH · GitHub CVSS 7.5

Frequently asked(5)

What is CVE-2026-53994?
CVE-2026-53994 is a high-severity vulnerability; its CVE record was published on July 18, 2026. ProFTPD modsftp contains a heap-based buffer overflow reachable by an authenticated SFTP user. The fxppacketread() function accepts the attacker-supplied 32-bit big-endian SFTP packet length without a minimum sanity check. A value of 0 causes an unsigned subtraction elsewhere in the read path to…
When was CVE-2026-53994 made public?
CVE-2026-53994 was made public on July 18, 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 18, 2026. EchelonGraph's copy of the record carries a last-modified date of October 24, 2026; the record at its source may have been updated since.
Is CVE-2026-53994 actively exploited?
CVE-2026-53994 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (38th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53994?
CVE-2026-53994 has a CVSS v3 base score of 6.5 (NVD). EchelonGraph synthesises NVD + FIRST EPSS + GHSA into a combined EG score of 7.5 (HIGH).
How do I remediate CVE-2026-53994?
A fix for CVE-2026-53994 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-53994 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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