CVE-2026-121958

HIGHNVD 7.58.8
EchelonGraph scoreMEDIUM confidence

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

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-11-04. NVD baseline CVSS 7.5; sources differ by 1.3.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Elevated

Also known asEUVD-2026-116958 (ENISA EUVD) · GHSA-449c-4f3m-649w (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: 0.3%CVSS: 7.5Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

FreeRDP through 3.32.1 has a heap out-of-bounds write in the RDPGFX client because the delete_surface callback truncates surface hash keys to 16 bits, leaving the surface table inconsistent so HashTable_GetKeys writes past its allocated key array. A malicious or man-in-the-middle RDP server can exploit this by creating surfaceId 0xFFFF, closing the RDPGFX channel, sending repeated DELETESURFACE PDUs, and then sending ENDFRAME or RESETGRAPHICS.

CVSS v3
7.5
EG Score
8.8HIGHmedium confidence
EG Risk
56
EG 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
0.3%
EPSS %ILE
23rd
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
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-10). 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 4, 2026

Last Modified

November 5, 2026

Advisory Details (2)

Auto-updated Nov 4, 2026
🔬 Proof of concept available. Patch available. Sources: github.
Web page

FreeRDP through 3.32.1 Heap Out-of-Bounds Write via RDPGFX HashTable_GetKeys | Advisories | VulnCheck

https://www.vulncheck.com/advisories/freerdp-through-3.32.1-heap-out-of-bounds-write-via-rdpgfx-hashtable-getkeys
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

FreeRDP RDPGFX client: heap out-of-bounds write in HashTable_GetKeys via surface-key truncation · Advisory · FreeRDP/FreeRDP · GitHub

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-m59q-wm7v-mp57

Vendor Advisories for CVE-2026-121958(3)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
freerdp22.10.0+dfsg1-1 ... 2.11.7+dfsg1-6~deb12u1 (13 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
freerdp33.15.0+dfsg-2.1 ... 3.33.0+dfsg-1 (51 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
freerdp33.15.0+dfsg-2.1 ... 3.32.1+dfsg-1~bpo13+1 (46 versions)
  • every version up to 3.32.2+dfsg-1: fixed in 3.32.2+dfsg-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 16× 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.

  1. 2026-11-13 16:50 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  2. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  3. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  4. 2026-11-11 03:48 UTCEchelonGraph re-scored
  5. 2026-11-11 03:48 UTCGHSA enrichmentGHSA-449c-4f3m-649w · GitHub severity HIGH · GitHub CVSS 8.8
  6. 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  7. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  8. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  9. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  10. 2026-11-06 16:36 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  11. 2026-11-05 19:27 UTCEchelonGraph re-scored
  12. 2026-11-05 19:27 UTCGHSA enrichmentGHSA-449c-4f3m-649w · GitHub severity HIGH · GitHub CVSS 8.8
  13. 2026-11-05 19:26 UTCNVD updateCVSS v3 → 7.5
  14. 2026-11-05 16:36 UTCEPSS rescoreEPSS 0.3% · 28th percentile
  15. 2026-11-04 19:26 UTCEchelonGraph re-scored
  16. 2026-11-04 19:26 UTCGHSA enrichmentGHSA-449c-4f3m-649w · GitHub severity HIGH · GitHub CVSS 8.8
  17. 2026-11-04 18:36 UTCEchelonGraph re-scored
  18. 2026-11-04 18:36 UTCGHSA enrichmentGHSA-449c-4f3m-649w · GitHub severity HIGH · GitHub CVSS 8.8
  19. 2026-11-04 17:03 UTCENISA EUVD ID recordedEUVD-2026-116958 · Source: ENISA EUVD
  20. 2026-11-04 16:27 UTCEchelonGraph re-scored
  21. 2026-11-04 15:41 UTCEchelonGraph re-scoredFirst assessed: 8.8 HIGH
  22. 2026-11-04 15:40 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-121958?
CVE-2026-121958 is a high-severity vulnerability; its CVE record was published on November 4, 2026. FreeRDP through 3.32.1 has a heap out-of-bounds write in the RDPGFX client because the delete_surface callback truncates surface hash keys to 16 bits, leaving the surface table inconsistent so HashTable_GetKeys writes past its allocated key array. A malicious or man-in-the-middle RDP server can…
When was CVE-2026-121958 made public?
CVE-2026-121958 was made public on October 20, 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 4, 2026. EchelonGraph's copy of the record carries a last-modified date of November 5, 2026; the record at its source may have been updated since.
Is CVE-2026-121958 actively exploited?
CVE-2026-121958 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (23rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-121958?
CVE-2026-121958 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + FIRST EPSS + GHSA into a combined EG score of 8.8 (HIGH).
How do I remediate CVE-2026-121958?
A fix for CVE-2026-121958 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-121958 are linked in the Vendor Advisories panel on this page.

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