Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, GenericOpenIdConnectBackend matches the identity provider email claim to an active account's delivery_email without rejecting an explicitly false email_verified claim. If a configured identity provider returns an email address that the authenticating user does not control together with email_verified=false, Zulip can log the user into the existing account for that address. Exploitation requires a misconfigured trusted identity provider, and deployments whose authoritative identity provider only emits email addresses controlled by the authenticating user are not affected. This issue is fixed in version 12.2.
CVE-2026-102893
CRITICALPre-NVD 9.19.1Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
“—” beside the score: it is equal to the CVSS score beside it.
This critical-severity CVE scores 9.1 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.4% (31st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Triggered by: Headline CVSS from the CNA's CVSS
Sources: the CNA's CVSS, EPSS
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).
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 9.1Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 9.1
- EG Score
- 9.1CRITICALmedium confidence
- EG Risk
- 56EG Risk 56/100
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 (value × EchelonGraph’s weight)Severity91% × 45%The EG Score, 9.1 of 10.Exploitation0.4% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (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
- 0.4%
- EPSS %ILE
- 31st
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (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.
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
October 14, 2026
Last Modified
October 15, 2026
Advisory Details (5)
Auto-updated Oct 14, 2026Patch available. Sources: github, github_pr, github_commit, github_release.
GitHub release Patch Available
Zulip Server 12.2
Patch available: zulip/zulip 12.2
https://github.com/zulip/zulip/releases/tag/12.2GitHub commit
commit b40f191a8c71 (zulip/zulip)
Fix landed in zulip/zulip commit b40f191a8c71 — awaiting tagged release
https://github.com/zulip/zulip/commit/b40f191a8c71e74fcb471f71de6a1233de157102GitHub commit Patch Available
commit 68d2d9defa39 (zulip/zulip)
Patch available: zulip/zulip 12.2 (contains commit 68d2d9defa39)
https://github.com/zulip/zulip/commit/68d2d9defa39f8af96a50fc7430efc34dee120b5GitHub pull request
12.2 patches for main
Fix merged in zulip/zulip PR #39913 on 2026-08-10 — awaiting tagged release
https://github.com/zulip/zulip/pull/39913GitHub advisoryMentions a patch (unverified)
OpenID Connect authentication ignores the email_verified claim · Advisory · zulip/zulip · GitHub
https://github.com/zulip/zulip/security/advisories/GHSA-xw9h-9rcm-hx4mWeakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× 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.
- 2026-10-15 19:20 UTCEG score recompute
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
- 2026-10-14 16:33 UTCEG score recompute
- 2026-10-14 16:00 UTCEG score recomputeFirst assessed: 9.1 CRITICAL
- 2026-10-14 15:59 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-102893?
CVE-2026-102893 is a critical-severity vulnerability; its CVE record was published on October 14, 2026. Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, GenericOpenIdConnectBackend matches the identity provider email claim to an active account's deliveryemail without rejecting an explicitly false emailverified claim. If a configured identity provider returns an…
When was the CVE record for CVE-2026-102893 published?
The CVE record for CVE-2026-102893 was published on October 14, 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 October 15, 2026; the record at its source may have been updated since.
Is CVE-2026-102893 actively exploited?
CVE-2026-102893 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-102893?
CVE-2026-102893 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-2026-102893?
A fix for CVE-2026-102893 is available: update to the fixed version the vendor names in its advisory.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-102893
Is Your Infrastructure Affected by CVE-2026-102893?
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