CVE-2026-18355

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-07. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: None knownExposed: 0

A fix is available — apply it.

A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), the wrapped-record length read from the wire is validated only against an upper bound. A small wire length (0, 1, or 2) produces an encrypted_buffer_count below the already-consumed encrypted_buffer_offset, causing an unsigned subtraction underflow in sasl_io_read_packet(). PR_Recv is then requested to read approximately 4 GiB into a 1024-byte heap buffer, resulting in a heap buffer overflow with attacker-controlled content. After a successful SASL bind with integrity protection (SSF > 0), a remote authenticated attacker can cause a denial of service or potentially achieve remote code execution. This flaw is distinct from CVE-2026-11774, whose fix only guards against upper-bound overflow.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
34(Track)
EG Risk 34/100SSVC: 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
Severity75% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
56%
KEV
Not listed

Published

September 7, 2026

Last Modified

September 8, 2026

Advisory Details (2)

Auto-updated Sep 7, 2026
Patch available. Sources: redhat.
redhat

2509186 – (CVE-2026-18355) CVE-2026-18355 389-ds-base: 389-ds-base: heap buffer overflow via SASL wrapped-record length lower-bound underflow in sasl_io_start_packet()

https://bugzilla.redhat.com/show_bug.cgi?id=2509186
redhat Patch Available

CVE-2026-18355 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-18355

Vendor Advisories for CVE-2026-18355(17)

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

Patch Availability(16)

Vendor / EcosystemFixed in / PatchReleasedSource
redhat389-ds-base-0:3.0.6-21.el10_02026-09-08redhat
redhat389-ds:1.4-8080020260831180218.6dbb38032026-09-08redhat
redhat389-ds-base-0:2.8.0-10.el9_82026-09-08redhat
redhat389-ds-base-0:3.2.0-10.el10_22026-09-08redhat
redhatredhat-ds:12-9020020260903155914.1674d5742026-09-08redhat
redhatredhat-ds:11-8100020260904171440.37ed7c032026-09-08redhat
redhatdirsrv/dirsrv-container-rhel10:17888517652026-09-08redhat
redhat389-ds:1.4-8040020260901171549.96015a922026-09-08redhat
redhat389-ds-base-0:2.6.1-24.el9_62026-09-08redhat
redhat389-ds-base-0:2.2.4-22.el9_22026-09-08redhat
redhat389-ds-base-0:1.3.11.1-15.el7_92026-09-08redhat
redhat389-ds:1.4-8060020260901145727.824efc522026-09-08redhat
redhatredhat-ds:12-9040020260903102623.1674d5742026-09-08redhat
redhat389-ds:1.4-8100020260904155442.25e700aa2026-09-08redhat
redhat389-ds-base-0:2.4.5-29.el9_42026-09-08redhat
redhatredhat-ds:11-8080020260903102346.f969626e2026-09-08redhat

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

(2 across 2 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
389-ds-base2.3.1+dfsg1-1 ... 3.3.0-2 (16 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
389-ds-base3.1.2+dfsg1-1 ... 3.3.0-2 (6 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 39× in last 7d / 85× 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.

  1. 2026-09-19 07:06 UTCVendor advisory
  2. 2026-09-19 07:05 UTCGHSA enrichment
  3. 2026-09-18 19:31 UTCEG score recompute
  4. 2026-09-18 19:31 UTCVendor advisory
  5. 2026-09-18 19:31 UTCGHSA enrichment
  6. 2026-09-18 19:27 UTCEPSS rescore
  7. 2026-09-18 07:54 UTCVendor advisory
  8. 2026-09-18 07:54 UTCGHSA enrichment
  9. 2026-09-17 20:20 UTCEG score recompute
  10. 2026-09-17 20:20 UTCVendor advisory
  11. 2026-09-17 20:20 UTCGHSA enrichment
  12. 2026-09-17 05:56 UTCVendor advisory
  13. 2026-09-17 05:56 UTCGHSA enrichment
  14. 2026-09-16 18:20 UTCEG score recompute
  15. 2026-09-16 18:20 UTCVendor advisory
  16. 2026-09-16 18:19 UTCGHSA enrichment
  17. 2026-09-16 14:07 UTCEPSS rescore
  18. 2026-09-16 05:52 UTCEG score recompute
  19. 2026-09-16 05:52 UTCVendor advisory
  20. 2026-09-16 05:52 UTCGHSA enrichment
  21. 2026-09-16 05:14 UTCEPSS rescore
  22. 2026-09-15 18:18 UTCVendor advisory
  23. 2026-09-15 18:18 UTCGHSA enrichment
  24. 2026-09-15 06:42 UTCEG score recompute
  25. 2026-09-15 06:42 UTCVendor advisory
Show 60 more
  1. 2026-09-15 06:42 UTCGHSA enrichment
  2. 2026-09-14 19:08 UTCVendor advisory
  3. 2026-09-14 19:08 UTCGHSA enrichment
  4. 2026-09-14 07:34 UTCVendor advisory
  5. 2026-09-14 07:34 UTCGHSA enrichment
  6. 2026-09-13 20:00 UTCEG score recompute
  7. 2026-09-13 20:00 UTCVendor advisory
  8. 2026-09-13 20:00 UTCGHSA enrichment
  9. 2026-09-13 16:46 UTCEPSS rescore
  10. 2026-09-13 08:25 UTCVendor advisory
  11. 2026-09-13 08:25 UTCGHSA enrichment
  12. 2026-09-12 20:52 UTCEG score recompute
  13. 2026-09-12 20:52 UTCVendor advisory
  14. 2026-09-12 20:52 UTCGHSA enrichment
  15. 2026-09-12 15:00 UTCEPSS rescore
  16. 2026-09-12 09:18 UTCVendor advisory
  17. 2026-09-12 09:18 UTCGHSA enrichment
  18. 2026-09-11 21:44 UTCEG score recompute
  19. 2026-09-11 21:44 UTCVendor advisory
  20. 2026-09-11 21:44 UTCGHSA enrichment
  21. 2026-09-11 14:52 UTCEPSS rescore
  22. 2026-09-11 10:10 UTCEG score recompute
  23. 2026-09-11 10:10 UTCVendor advisory
  24. 2026-09-11 10:10 UTCGHSA enrichment
  25. 2026-09-11 09:36 UTCEPSS rescore
  26. 2026-09-10 22:34 UTCVendor advisory
  27. 2026-09-10 22:34 UTCGHSA enrichment
  28. 2026-09-10 10:59 UTCEG score recompute
  29. 2026-09-10 10:59 UTCVendor advisory
  30. 2026-09-10 10:59 UTCGHSA enrichment
  31. 2026-09-10 09:34 UTCEPSS rescore
  32. 2026-09-09 23:18 UTCVendor advisory
  33. 2026-09-09 23:18 UTCGHSA enrichment
  34. 2026-09-09 10:09 UTCVendor advisory
  35. 2026-09-09 10:09 UTCGHSA enrichment
  36. 2026-09-08 22:35 UTCEG score recompute
  37. 2026-09-08 22:34 UTCGHSA enrichment
  38. 2026-09-08 22:04 UTCEG score recompute
  39. 2026-09-08 22:04 UTCGHSA enrichment
  40. 2026-09-08 22:00 UTCEPSS rescore
  41. 2026-09-08 19:51 UTCGHSA enrichment
  42. 2026-09-08 18:14 UTCEG score recompute
  43. 2026-09-08 18:14 UTCGHSA enrichment
  44. 2026-09-08 17:01 UTCEG score recompute
  45. 2026-09-08 17:01 UTCGHSA enrichment
  46. 2026-09-08 08:35 UTCGHSA enrichment
  47. 2026-09-08 07:30 UTCEG score recompute
  48. 2026-09-08 07:30 UTCGHSA enrichment
  49. 2026-09-08 06:39 UTCEG score recompute
  50. 2026-09-08 06:39 UTCGHSA enrichment
  51. 2026-09-08 06:23 UTCGHSA enrichment
  52. 2026-09-08 05:18 UTCGHSA enrichment
  53. 2026-09-08 04:19 UTCEG score recompute
  54. 2026-09-08 04:19 UTCGHSA enrichment
  55. 2026-09-08 03:30 UTCGHSA enrichment
  56. 2026-09-08 02:30 UTCEG score recompute
  57. 2026-09-08 02:30 UTCGHSA enrichment
  58. 2026-09-07 15:23 UTCEG score recompute
  59. 2026-09-07 14:28 UTCEG score recompute
  60. 2026-09-07 14:26 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18355?
CVE-2026-18355 is a high vulnerability published on September 7, 2026. A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasliostartpacket(), the wrapped-record length read from the wire is validated only against an upper bound. A small wire length (0, 1, or 2) produces an encryptedbuffercount below the…
When was CVE-2026-18355 disclosed?
CVE-2026-18355 was first published in the National Vulnerability Database on September 7, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18355 actively exploited?
CVE-2026-18355 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 43.8% of all scored CVEs.
What is the CVSS score of CVE-2026-18355?
CVE-2026-18355 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-18355?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18355, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-18355

Explore →

Is Your Infrastructure Affected by CVE-2026-18355?

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

Start Free Scan →Browse All CVEs