C-Kermit 8.0.200 before 11.1.515 contains a buffer overflow vulnerability in getreply() in ckcftp.c that allows malicious FTP servers to overwrite client memory by sending overlong security replies. Attackers controlling or intercepting an FTP server can send long PBSZ replies after AUTH TLS, or long ADAT replies in GSSAPI, Kerberos 4, and SRP builds, overflowing the static reply_buf with attacker-controlled bytes.
CVE-2026-129123
HIGHPre-NVD 8.88.8ElevatedEG-KEV Tier 3: ElevatedEG-KEV is EchelonGraph's own tiering of exploitation signals from CISA KEV, CISA's SSVC data (Vulnrichment), ransomware data, public exploit-code references and EPSS.Tier 3 is not evidence of exploitation. It means public exploit code is referenced, or CISA's SSVC data says "public PoC", or EPSS ranks the CVE in the top 5%.Signals for this CVE: CISA's SSVC exploitation value: public PoC.EchelonGraph confidence 38%: a heuristic from the tier and the number of signals, not a measured probability.
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-11-13. A secondary CVSS source baseline 8.8; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: GitHub Security Advisory, a secondary CVSS source
Also known asEUVD-2026-125556 (ENISA EUVD) · GHSA-f8jp-whmp-v2jf (GitHub Security Advisories)Source: ENISA EUVD
8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
- CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 8.8Exploit: No code on recordExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 8.8
- EG Score
- 8.8HIGHhigh confidence
- EG Risk
- 56EG Risk 56/100
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)Severity88% × 45%Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.Exploitation public PoC (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 at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.6%
- EPSS %ILE
- 49th
- 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 (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.6% 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, Track* at medium and Attend at high mission impact.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, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track 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 (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.
The score's inputs: 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
November 13, 2026
Last Modified
November 13, 2026
Advisory Details (5)
Auto-updated Nov 13, 2026🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
Web page
C-Kermit 8.0.200 before 11.1.515 FTP Client Buffer Overflow via PBSZ and ADAT Replies | Advisories | VulnCheck
https://www.vulncheck.com/advisories/c-kermit-8.0.200-before-11.1.515-ftp-client-buffer-overflow-via-pbsz-and-adat-repliesWeb page
ckermit/ckcftp.c at v11.0.514 · OpenKermit/ckermit · GitHub
https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcftp.c#L11161GitHub release Patch Available
v11.1.515
Patch available: OpenKermit/ckermit v11.1.515
https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515GitHub commit
commit bec28a4d5440 (OpenKermit/ckermit)
Fix landed in OpenKermit/ckermit commit bec28a4d5440 — awaiting tagged release
https://github.com/OpenKermit/ckermit/commit/bec28a4d544031fa07a07aacba3df5dd1202ef69GitHub advisoryMentions a patch (unverified)🟡 PoC Available
Remote code execution in C-Kermit · Advisory · OpenKermit/ckermit · GitHub
https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8pVendor Advisories for CVE-2026-129123(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.
- 2026-11-14 16:39 UTCEPSS rescoreEPSS 0.6% · 49th percentile
- 2026-11-13 22:28 UTCEchelonGraph re-scored
- 2026-11-13 22:28 UTCGHSA enrichmentGHSA-f8jp-whmp-v2jf · GitHub severity HIGH · GitHub CVSS 8.8
- 2026-11-13 21:42 UTCEchelonGraph re-scored
- 2026-11-13 21:42 UTCGHSA enrichmentGHSA-f8jp-whmp-v2jf · GitHub severity HIGH · GitHub CVSS 8.8
- 2026-11-13 21:23 UTCEchelonGraph re-scored
- 2026-11-13 21:23 UTCGHSA enrichmentGHSA-f8jp-whmp-v2jf · GitHub severity HIGH · GitHub CVSS 8.8
- 2026-11-13 17:29 UTCEchelonGraph re-scored
- 2026-11-13 17:01 UTCENISA EUVD ID recordedEUVD-2026-125556 · Source: ENISA EUVD
- 2026-11-13 16:37 UTCEchelonGraph re-scoredFirst assessed: 8.8 HIGH
- 2026-11-13 16:31 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-129123?
CVE-2026-129123 is a high-severity vulnerability; its CVE record was published on November 13, 2026. C-Kermit 8.0.200 before 11.1.515 contains a buffer overflow vulnerability in getreply() in ckcftp.c that allows malicious FTP servers to overwrite client memory by sending overlong security replies. Attackers controlling or intercepting an FTP server can send long PBSZ replies after AUTH TLS, or…
When was CVE-2026-129123 made public?
CVE-2026-129123 was made public on October 31, 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 November 13, 2026. EchelonGraph's copy of the record carries a last-modified date of November 13, 2026; the record at its source may have been updated since.
Is CVE-2026-129123 actively exploited?
CVE-2026-129123 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-129123?
CVE-2026-129123 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-129123?
A fix for CVE-2026-129123 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-129123 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-129123
Is Your Infrastructure Affected by CVE-2026-129123?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.