CVE-2026-59163

CRITICALPre-NVD 9.19.1
EchelonGraph scoreMEDIUM confidence

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

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-18. A secondary CVSS source baseline 9.1; 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 weekElevated

Also known asEUVD-2026-83263 (ENISA EUVD) · GHSA-xcw4-53cc-hv32 (GitHub Security Advisories)Source: ENISA EUVD

9.1EG
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: 9.1Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Mnemosyne is a memory layer for artificial intelligence agents. Prior to v3.10.1, the auth check in mnemosyne/core/sync_server.py parsed the JWT's header and payload using base64 decoding, then passed the token to a jwt library call with options that effectively disabled signature verification. The server accepted any well-formed token regardless of the signature, including tokens with alg: none and tokens signed with the wrong key. The fix in v3.10.1 replaces the broken decode with a from-scratch HS256 verifier using only the Python standard library. For users who cannot upgrade immediately, restrict network access to the sync server endpoint to trusted clients only. Firewall, reverse proxy with mTLS, or localhost bind with SSH tunnel are all viable. The vulnerability is not exploitable against an unreachable endpoint.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
72
EG Risk 72/100

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)
Severity91% × 45%
Impact severity (EG Severity): CVSS 9.1 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.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (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 yes (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
25th
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 (9.1): severity, escalated by confirmed exploitation. This CVE's 9.1 is its impact severity (EG Severity), not escalated.

EG Severity
9.1 CRITICALCVSS-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 2026-11-01). 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: 3 days if the affected system is publicly exposed; 60 days 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 yes (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)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

September 18, 2026

Last Modified

September 24, 2026

Advisory Details (4)

Auto-updated Sep 18, 2026
Patch available. Sources: github_pr, github_commit, github_release, github.
GitHub release Patch Available

v3.10.1

Patch available: mnemosyne-oss/mnemosyne v3.10.1

https://github.com/mnemosyne-oss/mnemosyne/releases/tag/v3.10.1
GitHub commit Patch Available

commit a0b6b8711a1a (mnemosyne-oss/mnemosyne)

Patch available: mnemosyne-oss/mnemosyne v3.10.1 (contains commit a0b6b8711a1a)

https://github.com/mnemosyne-oss/mnemosyne/commit/a0b6b8711a1a485304971710dc3571e29ff9dbeb
GitHub pull request Patch Available

chore: release: v3.10.1 — critical JWT signature verification fix (CVE GHSA-xcw4-53cc-hv32)

Patch available: mnemosyne-oss/mnemosyne v3.10.1 (PR #373 merged 2026-06-22)

https://github.com/mnemosyne-oss/mnemosyne/pull/373
GitHub advisoryMentions a patch (unverified)

JWT signature verification bypass in Mnemosyne sync server allows authentication bypass · Advisory · mnemosyne-oss/mnemosyne · GitHub

https://github.com/mnemosyne-oss/mnemosyne/security/advisories/GHSA-xcw4-53cc-hv32

Vendor Advisories for CVE-2026-59163(1)

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
pipmnemosyne-memory @ 3.10.1 (fixes <= 3.10.0)—ghsa

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

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
mnemosyne-memory1.10.1 ... 3.9.0 (25 versions)
  • every version up to 3.10.1: fixed in 3.10.1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 17× in last 7d / 66× 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.

  1. 2026-11-02 14:50 UTCEG score recompute
  2. 2026-11-02 14:50 UTCGHSA enrichmentGHSA-xcw4-53cc-hv32 · GitHub severity CRITICAL · GitHub CVSS 9.1
  3. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  4. 2026-11-01 14:05 UTCGHSA enrichmentGHSA-xcw4-53cc-hv32 · GitHub severity CRITICAL · GitHub CVSS 9.1
  5. 2026-11-01 07:42 UTCGHSA enrichmentGHSA-xcw4-53cc-hv32 · GitHub severity CRITICAL · GitHub CVSS 9.1
  6. 2026-11-01 07:42 UTCEG score recompute
  7. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  8. 2026-10-31 13:20 UTCEG score recompute
  9. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  10. 2026-10-30 12:35 UTCEG score recompute
  11. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  12. 2026-10-29 11:47 UTCEG score recompute
  13. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  14. 2026-10-28 11:02 UTCEG score recompute
  15. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  16. 2026-10-27 09:27 UTCEG score recompute
  17. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  18. 2026-10-26 08:38 UTCEG score recompute
  19. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  20. 2026-10-25 14:16 UTCEG score recompute
  21. 2026-10-25 07:54 UTCEG score recompute
  22. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  23. 2026-10-24 07:09 UTCEG score recompute
  24. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  25. 2026-10-23 06:25 UTCEG score recompute
Show 71 more
  1. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  2. 2026-10-22 05:40 UTCEG score recompute
  3. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  4. 2026-10-21 04:55 UTCEG score recompute
  5. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  6. 2026-10-20 04:11 UTCEG score recompute
  7. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  8. 2026-10-19 03:20 UTCEG score recompute
  9. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  10. 2026-10-18 03:27 UTCEG score recompute
  11. 2026-10-18 02:35 UTCEG score recompute
  12. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  13. 2026-10-17 01:51 UTCEG score recompute
  14. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  15. 2026-10-16 01:06 UTCEG score recompute
  16. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  17. 2026-10-14 20:08 UTCEG score recompute
  18. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  19. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  20. 2026-10-13 16:16 UTCEG score recompute
  21. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  22. 2026-10-12 15:32 UTCEG score recompute
  23. 2026-10-11 19:36 UTCEG score recompute
  24. 2026-10-11 16:51 UTCEG score recompute
  25. 2026-10-11 14:14 UTCEG score recompute
  26. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  27. 2026-10-11 11:23 UTCEG score recompute
  28. 2026-10-10 23:20 UTCEG score recompute
  29. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  30. 2026-10-09 20:40 UTCEG score recompute
  31. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  32. 2026-10-08 17:25 UTCEG score recompute
  33. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  34. 2026-10-08 01:44 UTCEG score recompute
  35. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  36. 2026-10-06 18:44 UTCEG score recompute
  37. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  38. 2026-10-05 19:57 UTCEG score recompute
  39. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  40. 2026-10-05 01:04 UTCEG score recompute
  41. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  42. 2026-10-03 14:46 UTCEG score recompute
  43. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  44. 2026-10-02 19:50 UTCEG score recompute
  45. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  46. 2026-10-02 00:07 UTCEG score recompute
  47. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  48. 2026-09-30 16:50 UTCEG score recompute
  49. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  50. 2026-09-29 15:30 UTCEG score recompute
  51. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  52. 2026-09-29 00:20 UTCEG score recompute
  53. 2026-09-28 16:43 UTCEG score recompute
  54. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  55. 2026-09-27 14:06 UTCEG score recompute
  56. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  57. 2026-09-26 19:09 UTCEG score recompute
  58. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  59. 2026-09-26 04:01 UTCEG score recompute
  60. 2026-09-24 15:11 UTCEG score recompute
  61. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  62. 2026-09-23 20:08 UTCEG score recompute
  63. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  64. 2026-09-22 17:40 UTCEG score recompute
  65. 2026-09-21 22:27 UTCEG score recompute
  66. 2026-09-20 23:37 UTCEG score recompute
  67. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  68. 2026-09-19 17:14 UTCEG score recompute
  69. 2026-09-18 18:27 UTCEG score recompute
  70. 2026-09-18 18:00 UTCEG score recomputeFirst assessed: 9.1 CRITICAL
  71. 2026-09-18 17:59 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-59163?
CVE-2026-59163 is a critical-severity vulnerability; its CVE record was published on September 18, 2026. Mnemosyne is a memory layer for artificial intelligence agents. Prior to v3.10.1, the auth check in mnemosyne/core/sync_server.py parsed the JWT's header and payload using base64 decoding, then passed the token to a jwt library call with options that effectively disabled signature verification. The…
When was the CVE record for CVE-2026-59163 published?
The CVE record for CVE-2026-59163 was published on September 18, 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 24, 2026; the record at its source may have been updated since.
Is CVE-2026-59163 actively exploited?
CVE-2026-59163 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-59163?
CVE-2026-59163 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-59163?
A fix for CVE-2026-59163 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-59163 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-59163

Explore →

Is Your Infrastructure Affected by CVE-2026-59163?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.