CVE-2026-64620

CRITICALNVD 9.19.8▲
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-20. NVD baseline CVSS 9.1; sources differ by 0.7.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: None knownExposed: 0

A fix is available — apply it.

FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and only afterward checks output_length > out_length, so out-of-bounds bytes are written before the bounds check. On the server side, when a client selects RDP Standard Security, the encrypted client random is decrypted into a fixed 32-byte buffer. Because the server publishes its RSA public key, an unauthenticated attacker can forge a ciphertext whose decrypted value is up to the full modulus length (e.g. 256 bytes for RSA-2048), overflowing the 32-byte heap buffer by up to ~224 attacker-controlled bytes pre-authentication, resulting in denial of service.

CVSS v3
9.1
EG Score
9.8(medium)
EG Risk
59(Track)
EG Risk 59/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
56%
KEV
Not listed

Published

July 20, 2026

Last Modified

July 28, 2026

Advisory Details (3)

Auto-updated Sep 7, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
generic

FreeRDP before 3.28.0 Heap Buffer Overflow via crypto_rsa_common | Advisories | VulnCheck

https://www.vulncheck.com/advisories/freerdp-before-heap-buffer-overflow-via-crypto-rsa-common
github Patch Available🟡 PoC Available

Pre-auth server heap overflow: `crypto_rsa_common` writes the decrypted client random with `BN_bn2bin` before checking the 32-byte output buffer · Advisory · FreeRDP/FreeRDP · GitHub

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-pjqx-v446-x7fc
github_commit

commit 1f7a716d39b5 (FreeRDP/FreeRDP)

Fix landed in FreeRDP/FreeRDP commit 1f7a716d39b5 — awaiting tagged release

https://github.com/FreeRDP/FreeRDP/commit/1f7a716d39b5605bb8a83b0c3c97a6ce386609ef

Vendor Advisories for CVE-2026-64620(3)

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 / EcosystemFixed in / PatchReleasedSource
redhatfreerdp-2:3.10.3-3.el10_0.112026-08-24redhat
redhatfreerdp-2:3.10.3-12.el10_2.82026-08-13redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
freerdp22.10.0+dfsg1-1 ... 2.9.0+dfsg1-1~bpo11+1 (32 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
freerdp22.10.0+dfsg1-1 ... 2.11.7+dfsg1-6~deb12u1 (13 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
freerdp33.15.0+dfsg-2.1 ... 3.31.0+dfsg-1 (44 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
freerdp33.15.0+dfsg-2.1 ... 3.27.1+dfsg-1 (35 versions)3.28.0+dfsg-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 35× in last 7d / 244× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 406 total refreshes for this CVE.

  1. 2026-09-11 18:33 UTCEG score recompute
  2. 2026-09-11 18:33 UTCVendor advisory
  3. 2026-09-11 18:33 UTCGHSA enrichment
  4. 2026-09-11 14:53 UTCEPSS rescore
  5. 2026-09-11 09:37 UTCEPSS rescore
  6. 2026-09-11 09:31 UTCEG score recompute
  7. 2026-09-11 09:31 UTCVendor advisory
  8. 2026-09-11 09:30 UTCGHSA enrichment
  9. 2026-09-09 11:59 UTCEG score recompute
  10. 2026-09-09 11:59 UTCVendor advisory
  11. 2026-09-09 11:59 UTCGHSA enrichment
  12. 2026-09-08 22:01 UTCEPSS rescore
  13. 2026-09-08 02:58 UTCVendor advisory
  14. 2026-09-08 02:58 UTCGHSA enrichment
  15. 2026-09-07 22:58 UTCEG score recompute
  16. 2026-09-07 22:58 UTCVendor advisory
  17. 2026-09-07 22:58 UTCGHSA enrichment
  18. 2026-09-07 16:01 UTCEPSS rescore
  19. 2026-09-06 15:52 UTCEG score recompute
  20. 2026-09-06 15:52 UTCVendor advisory
  21. 2026-09-06 15:52 UTCGHSA enrichment
  22. 2026-09-06 13:47 UTCEPSS rescore
  23. 2026-09-06 11:48 UTCVendor advisory
  24. 2026-09-06 11:48 UTCGHSA enrichment
  25. 2026-09-06 04:15 UTCVendor advisory
Show 75 more
  1. 2026-09-06 04:14 UTCGHSA enrichment
  2. 2026-09-05 23:52 UTCVendor advisory
  3. 2026-09-05 23:52 UTCGHSA enrichment
  4. 2026-09-05 19:52 UTCEG score recompute
  5. 2026-09-05 19:52 UTCVendor advisory
  6. 2026-09-05 19:52 UTCGHSA enrichment
  7. 2026-09-05 15:31 UTCEPSS rescore
  8. 2026-09-05 09:36 UTCEG score recompute
  9. 2026-09-05 09:36 UTCVendor advisory
  10. 2026-09-05 09:36 UTCGHSA enrichment
  11. 2026-09-04 05:07 UTCEPSS rescore
  12. 2026-09-02 14:12 UTCEPSS rescore
  13. 2026-09-01 13:54 UTCEPSS rescore
  14. 2026-09-01 04:40 UTCEPSS rescore
  15. 2026-08-31 03:31 UTCVendor advisory
  16. 2026-08-31 03:31 UTCGHSA enrichment
  17. 2026-08-30 23:30 UTCVendor advisory
  18. 2026-08-30 23:30 UTCGHSA enrichment
  19. 2026-08-30 19:31 UTCEG score recompute
  20. 2026-08-30 19:31 UTCVendor advisory
  21. 2026-08-30 19:30 UTCGHSA enrichment
  22. 2026-08-30 19:17 UTCEPSS rescore
  23. 2026-08-30 15:31 UTCVendor advisory
  24. 2026-08-30 15:31 UTCGHSA enrichment
  25. 2026-08-30 10:56 UTCVendor advisory
  26. 2026-08-30 10:56 UTCGHSA enrichment
  27. 2026-08-30 06:40 UTCVendor advisory
  28. 2026-08-30 06:40 UTCGHSA enrichment
  29. 2026-08-30 02:39 UTCEG score recompute
  30. 2026-08-30 02:39 UTCVendor advisory
  31. 2026-08-30 02:39 UTCGHSA enrichment
  32. 2026-08-30 01:22 UTCEPSS rescore
  33. 2026-08-28 21:42 UTCEPSS rescore
  34. 2026-08-28 01:41 UTCVendor advisory
  35. 2026-08-28 01:41 UTCGHSA enrichment
  36. 2026-08-27 21:20 UTCEG score recompute
  37. 2026-08-27 21:20 UTCVendor advisory
  38. 2026-08-27 21:20 UTCGHSA enrichment
  39. 2026-08-27 11:44 UTCVendor advisory
  40. 2026-08-27 11:44 UTCGHSA enrichment
  41. 2026-08-27 02:10 UTCVendor advisory
  42. 2026-08-27 02:10 UTCGHSA enrichment
  43. 2026-08-26 22:10 UTCEG score recompute
  44. 2026-08-26 22:10 UTCVendor advisory
  45. 2026-08-26 22:10 UTCGHSA enrichment
  46. 2026-08-26 14:47 UTCEPSS rescore
  47. 2026-08-26 11:54 UTCVendor advisory
  48. 2026-08-26 11:54 UTCGHSA enrichment
  49. 2026-08-26 07:54 UTCVendor advisory
  50. 2026-08-26 07:54 UTCGHSA enrichment
  51. 2026-08-26 03:43 UTCVendor advisory
  52. 2026-08-26 03:43 UTCGHSA enrichment
  53. 2026-08-25 23:43 UTCVendor advisory
  54. 2026-08-25 23:43 UTCGHSA enrichment
  55. 2026-08-25 19:03 UTCVendor advisory
  56. 2026-08-25 19:03 UTCGHSA enrichment
  57. 2026-08-25 15:02 UTCEG score recompute
  58. 2026-08-25 15:02 UTCVendor advisory
  59. 2026-08-25 15:02 UTCGHSA enrichment
  60. 2026-08-25 13:49 UTCEPSS rescore
  61. 2026-08-25 11:01 UTCVendor advisory
  62. 2026-08-25 11:01 UTCGHSA enrichment
  63. 2026-08-25 07:02 UTCVendor advisory
  64. 2026-08-25 07:02 UTCGHSA enrichment
  65. 2026-08-25 03:01 UTCVendor advisory
  66. 2026-08-25 03:01 UTCGHSA enrichment
  67. 2026-08-24 22:59 UTCVendor advisory
  68. 2026-08-24 22:59 UTCGHSA enrichment
  69. 2026-08-24 19:00 UTCEG score recompute
  70. 2026-08-24 19:00 UTCVendor advisory
  71. 2026-08-24 19:00 UTCGHSA enrichment
  72. 2026-08-24 13:02 UTCEG score recompute
  73. 2026-08-24 13:02 UTCVendor advisory
  74. 2026-08-24 13:02 UTCGHSA enrichment
  75. 2026-08-24 09:01 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-64620?
CVE-2026-64620 is a critical vulnerability published on July 20, 2026. FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in cryptorsacommon() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BNbn2bin() and only afterward checks outputlength > out_length, so…
When was CVE-2026-64620 disclosed?
CVE-2026-64620 was first published in the National Vulnerability Database on July 20, 2026, with the most recent update on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64620 actively exploited?
CVE-2026-64620 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 43.9% of all scored CVEs.
What is the CVSS score of CVE-2026-64620?
CVE-2026-64620 has a CVSS v3 base score of 9.1 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.8.
How do I remediate CVE-2026-64620?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64620, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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