CVE-2026-39944

HIGHPre-NVD 8.88.8
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (21st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-67315 (ENISA EUVD)Source: ENISA EUVD

8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the RADOS Gateway (RGW) protects STS session tokens with an AES-128-CBC handler that provides no message authentication, allowing an attacker who holds any valid STS token to tamper with it undetected and escalate to full RGW administrative access. Because the ciphertext is unauthenticated, the attacker can perform a CBC bit-flip on the acct_type, perm_type, and is_admin fields of their own token, and a forged is_admin value triggers a global administrative override that bypasses all capability checks. The attack is reachable remotely over the RGW S3 endpoint and is a self-contained modification of a token the attacker already possesses, requiring no encryption oracle and no network observation. It requires only a single valid STS token, which need not carry any elevated privileges, with STS enabled. This issue is fixed in versions 20.2.4 and 19.2.6.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
40
EG Risk 40/100

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.
Exploitation0.3% × 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
0.3%
EPSS %ILE
21st
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.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-08). 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, 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 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.

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

August 27, 2026

Last Modified

September 8, 2026

Advisory Details (1)

Auto-updated Aug 27, 2026
Patch available. Sources: github.
GitHub advisoryMentions a patch (unverified)

Ceph RGW STS tokens vulnerable to CBC bit-flip privilege escalation to RGW admin · Advisory · ceph/ceph · GitHub

https://github.com/ceph/ceph/security/advisories/GHSA-j73r-qrgx-jvq2

Vendor Advisories for CVE-2026-39944(2)

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

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatceph-2:19.2.1-423.el9cp2026-10-08redhat
redhatrhceph/rhceph-8-rhel9:17911769902026-10-08redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ceph16.2.11+ds-2 ... 20.2.4+ds-1 (63 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
ceph18.2.7+ds-1 ... 20.2.4+ds-1 (20 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ceph18.2.7+ds-1 ... 20.2.2+ds-9 (18 versions)
  • every version up to 20.2.4+ds-1: fixed in 20.2.4+ds-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 34× 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.

Showing the most recent 100 of 135 rows on record for this CVE, as 99 entries (1 repeat merged).

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. 1 repeat row among the latest 100 is merged into the row it repeats. The 35 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:52 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  2. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  3. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  4. 2026-11-10 16:43 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  5. 2026-11-09 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  6. 2026-11-09 01:24 UTCEchelonGraph re-scored
  7. 2026-11-09 01:24 UTCVendor advisory
  8. 2026-11-08 16:39 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  9. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  10. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  11. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  12. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  13. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  14. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  15. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  16. 2026-11-01 13:56 UTCEchelonGraph re-scored
  17. 2026-11-01 13:56 UTCVendor advisory
  18. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  19. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  20. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  21. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  22. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  23. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  24. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  25. 2026-10-25 14:31 UTCEchelonGraph re-scored
Show 74 more
  1. 2026-10-25 02:26 UTCEchelonGraph re-scored
  2. 2026-10-25 02:26 UTCVendor advisory
  3. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  4. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  5. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  6. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  7. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  8. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  9. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  10. 2026-10-18 03:43 UTCEchelonGraph re-scored
  11. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  12. 2026-10-17 14:57 UTCEchelonGraph re-scored
  13. 2026-10-17 14:57 UTCVendor advisory
  14. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  15. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  16. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  17. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  18. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  19. 2026-10-12 16:10 UTCEchelonGraph re-scored
  20. 2026-10-11 19:52 UTCEchelonGraph re-scored
  21. 2026-10-11 17:05 UTCEchelonGraph re-scored
  22. 2026-10-11 14:32 UTCEchelonGraph re-scored
  23. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  24. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  25. 2026-10-10 13:46 UTCVendor advisory
  26. 2026-10-10 01:45 UTCEchelonGraph re-scored
  27. 2026-10-10 01:45 UTCVendor advisory
  28. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  29. 2026-10-09 02:55 UTCEchelonGraph re-scored
  30. 2026-10-09 02:55 UTCVendor advisory
  31. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  32. 2026-10-08 01:13 UTCEchelonGraph re-scored
  33. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  34. 2026-10-07 02:53 UTCEchelonGraph re-scored
  35. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  36. 2026-10-06 02:28 UTCEchelonGraph re-scored
  37. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  38. 2026-10-05 02:36 UTCEchelonGraph re-scored
  39. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  40. 2026-10-03 14:56 UTCEchelonGraph re-scored
  41. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  42. 2026-10-02 19:48 UTCEchelonGraph re-scored
  43. 2026-10-01 19:52 UTCEchelonGraph re-scored
  44. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  45. 2026-09-30 19:53 UTCEchelonGraph re-scored
  46. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  47. 2026-09-30 04:53 UTCEchelonGraph re-scored
  48. 2026-09-29 12:12 UTCEchelonGraph re-scored
  49. 2026-09-28 21:12 UTCEchelonGraph re-scored
  50. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  51. 2026-09-27 18:36 UTCEchelonGraph re-scored
  52. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  53. 2026-09-26 18:23 UTCEchelonGraph re-scored
  54. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  55. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  56. 2026-09-24 23:28 UTCEchelonGraph re-scored
  57. 2026-09-23 23:27 UTCEchelonGraph re-scored
  58. 2026-09-22 23:40 UTCEchelonGraph re-scored
  59. 2026-09-21 23:39 UTCEchelonGraph re-scored
  60. 2026-09-20 23:50 UTCEchelonGraph re-scored
  61. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  62. 2026-09-19 23:37 UTCEchelonGraph re-scored
  63. 2026-09-18 23:49 UTCEchelonGraph re-scored
  64. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  65. 2026-09-18 00:02 UTCEchelonGraph re-scored
  66. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  67. 2026-09-16 23:22 UTCEchelonGraph re-scored
  68. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  69. 2026-09-16 11:28 UTCEchelonGraph re-scored
  70. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  71. 2026-09-15 11:32 UTCEchelonGraph re-scored
  72. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  73. 2026-09-13 23:25 UTCEchelonGraph re-scored
  74. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile

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Frequently asked(5)

What is CVE-2026-39944?
CVE-2026-39944 is a high-severity vulnerability; its CVE record was published on August 27, 2026. Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the RADOS Gateway (RGW) protects STS session tokens with an AES-128-CBC handler that provides no message authentication, allowing an attacker who holds any valid…
When was the CVE record for CVE-2026-39944 published?
The CVE record for CVE-2026-39944 was published on August 27, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 8, 2026; the record at its source may have been updated since.
Is CVE-2026-39944 actively exploited?
CVE-2026-39944 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (21st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-39944?
CVE-2026-39944 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-2026-39944?
A fix for CVE-2026-39944 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-39944 are linked in the Vendor Advisories panel on this page.

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