CVE-2026-87853

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

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

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2026-75084 (ENISA EUVD) · GHSA-993g-jgf7-rg3x (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
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: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A flaw was found in SSSD's IdP authentication provider. The eval_access_token_buf() function compares the OIDC subject identifier using strncmp() with the authenticated user's identifier length, performing a prefix comparison instead of an exact match. An attacker whose IdP identifier is a strict prefix of a target user's identifier can authenticate as the target user.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 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
27th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 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. 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

September 9, 2026

Last Modified

November 11, 2026

Advisory Details (2)

Auto-updated Sep 9, 2026
Patch available. Sources: redhat.
Red Hat

2530888 – (CVE-2026-87853) CVE-2026-87853 sssd: sssd: IdP authentication prefix comparison allows cross-user impersonation

https://bugzilla.redhat.com/show_bug.cgi?id=2530888
Red HatMentions a patch (unverified)

CVE-2026-87853 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 10.2 is the first and only RHEL version that ships the IdP provider feature. RHEL 10.1, despite shippi

https://access.redhat.com/security/cve/CVE-2026-87853

Vendor Advisories for CVE-2026-87853(2)

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
redhatsssd-0:2.12.0-3.el10_2.22026-10-08redhat

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
sssd2.10.1-1 ... 2.9.5-5 (27 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
sssd2.10.1-2 ... 2.13.1-4 (12 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
sssd2.10.1-2 ... 2.13.1-4 (12 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 54× 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 213 rows on record for this CVE.

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. None are among the latest 100 rows. The 113 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:58 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  2. 2026-11-12 16:35 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  3. 2026-11-11 16:41 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  4. 2026-11-11 13:28 UTCEchelonGraph re-scored
  5. 2026-11-11 13:28 UTCVendor advisory
  6. 2026-11-11 13:27 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  7. 2026-11-11 13:06 UTCEchelonGraph re-scored
  8. 2026-11-11 13:06 UTCVendor advisory
  9. 2026-11-11 13:06 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  10. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  11. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  12. 2026-11-08 16:41 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  13. 2026-11-07 16:40 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  14. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  15. 2026-11-06 02:27 UTCEchelonGraph re-scored
  16. 2026-11-06 02:27 UTCVendor advisory
  17. 2026-11-06 02:27 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  18. 2026-11-06 01:23 UTCEchelonGraph re-scored
  19. 2026-11-06 01:23 UTCVendor advisory
  20. 2026-11-06 01:23 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  21. 2026-11-05 16:39 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  22. 2026-11-04 16:37 UTCEPSS rescoreEPSS 0.3% · 26th percentile
  23. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  24. 2026-11-03 07:27 UTCEchelonGraph re-scored
  25. 2026-11-03 07:27 UTCVendor advisory
Show 75 more
  1. 2026-11-03 07:27 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  2. 2026-11-03 06:28 UTCEchelonGraph re-scored
  3. 2026-11-03 06:28 UTCVendor advisory
  4. 2026-11-03 06:28 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  5. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  6. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  7. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  8. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  9. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  10. 2026-10-29 06:26 UTCEchelonGraph re-scored
  11. 2026-10-29 06:26 UTCVendor advisory
  12. 2026-10-29 06:26 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  13. 2026-10-29 05:33 UTCEchelonGraph re-scored
  14. 2026-10-29 05:33 UTCVendor advisory
  15. 2026-10-29 05:33 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  17. 2026-10-28 15:19 UTCEchelonGraph re-scored
  18. 2026-10-28 15:19 UTCVendor advisory
  19. 2026-10-28 15:19 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  20. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  21. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  22. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  23. 2026-10-25 13:53 UTCEchelonGraph re-scored
  24. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  25. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  26. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  27. 2026-10-21 19:28 UTCEchelonGraph re-scored
  28. 2026-10-21 19:28 UTCVendor advisory
  29. 2026-10-21 19:27 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  30. 2026-10-21 18:56 UTCEchelonGraph re-scored
  31. 2026-10-21 18:56 UTCVendor advisory
  32. 2026-10-21 18:56 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  33. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  34. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  35. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  36. 2026-10-19 16:09 UTCEchelonGraph re-scored
  37. 2026-10-19 16:09 UTCVendor advisory
  38. 2026-10-19 16:08 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  39. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  40. 2026-10-18 03:03 UTCEchelonGraph re-scored
  41. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  42. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  43. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  44. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  45. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  46. 2026-10-13 05:05 UTCEchelonGraph re-scored
  47. 2026-10-13 05:05 UTCVendor advisory
  48. 2026-10-13 05:05 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  49. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  50. 2026-10-12 14:49 UTCEchelonGraph re-scored
  51. 2026-10-11 22:24 UTCVendor advisory
  52. 2026-10-11 22:24 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  53. 2026-10-11 19:16 UTCEchelonGraph re-scored
  54. 2026-10-11 16:33 UTCEchelonGraph re-scored
  55. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  56. 2026-10-11 13:49 UTCEchelonGraph re-scored
  57. 2026-10-11 10:19 UTCVendor advisory
  58. 2026-10-11 10:19 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  59. 2026-10-10 20:14 UTCEchelonGraph re-scored
  60. 2026-10-10 20:14 UTCVendor advisory
  61. 2026-10-10 20:14 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  62. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  63. 2026-10-10 08:17 UTCEchelonGraph re-scored
  64. 2026-10-10 08:17 UTCVendor advisory
  65. 2026-10-10 08:17 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  66. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  67. 2026-10-09 20:06 UTCEchelonGraph re-scored
  68. 2026-10-09 20:06 UTCVendor advisory
  69. 2026-10-09 20:06 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  70. 2026-10-09 00:21 UTCEchelonGraph re-scored
  71. 2026-10-09 00:21 UTCVendor advisory
  72. 2026-10-09 00:21 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  73. 2026-10-08 23:33 UTCEchelonGraph re-scored
  74. 2026-10-08 23:33 UTCGHSA enrichmentGHSA-993g-jgf7-rg3x · GitHub severity HIGH · GitHub CVSS 7.5
  75. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 39th percentile

Frequently asked(5)

What is CVE-2026-87853?
CVE-2026-87853 is a high-severity vulnerability; its CVE record was published on September 9, 2026. A flaw was found in SSSD's IdP authentication provider. The eval_access_token_buf() function compares the OIDC subject identifier using strncmp() with the authenticated user's identifier length, performing a prefix comparison instead of an exact match. An attacker whose IdP identifier is a strict…
When was CVE-2026-87853 made public?
CVE-2026-87853 was made public on September 9, 2026: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on September 9, 2026. EchelonGraph's copy of the record carries a last-modified date of November 11, 2026; the record at its source may have been updated since.
Is CVE-2026-87853 actively exploited?
CVE-2026-87853 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (27th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-87853?
CVE-2026-87853 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-87853?
A fix for CVE-2026-87853 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-87853 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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