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Security Digest · Vulnerability record · Known exploited

CVE-2023-42793: JetBrains TeamCity Authentication Bypass Vulnerability

Exploited in the wild (CISA KEV). In JetBrains TeamCity before 2023.05.4 authentication bypass leading to RCE on TeamCity Server was possible

CISA KEV · added 2023-10-04 CVSS 9.8 Critical EPSS 100.0% · p100.0

Updated By erroneo.us Security Desk11 references Seen in the digest for Oct 4, 2023

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

  • Yes, if you run JetBrains TeamCity. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2023-10-04, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2023-10-25; treat that as the outer limit, not the target. CISA also lists it as known to be used in ransomware campaigns.
  • EPSS 100.0%, percentile 100.0: FIRST’s model estimates a 100.0% chance of exploitation activity in the next 30 days, higher than 100.0% of all scored CVEs (very high). EPSS is a probability, not a verdict.
  • Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

What it is

In JetBrains TeamCity before 2023.05.4 authentication bypass leading to RCE on TeamCity Server was possible

CISA’s summary

JetBrains TeamCity contains an authentication bypass vulnerability that allows for remote code execution on TeamCity Server.

Weakness type: CWE-288.

Product: JetBrains TeamCity · Assigned by: JetBrains · Published: 2023-09-19

Affected and fixed versions

VendorProductAffected versions (per CVE record)
JetBrainsTeamCity< 2023.05.4

Severity scores

Scored byCVSSScoreVector
JetBrains3.19.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • Attack vector: network (remotely reachable)
  • Attack complexity: low
  • Privileges required: none (no login)
  • User interaction: none
  • Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

  • CISA KEV: added 2023-10-04; federal due date 2023-10-25. Known ransomware use: Known.
  • CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
  • CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
  • FIRST EPSS (model of 2026-10-21): 99.99% probability of exploitation activity in the next 30 days; percentile 100.0.

Timeline

  • — CVE record published by JetBrains
  • — Added to CISA’s Known Exploited Vulnerabilities catalog
  • — CISA remediation deadline for US federal agencies
  • — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

  1. Listed in CISA KEV notes (blog.jetbrains.com) blog.jetbrains.com

Vulnerability records

  1. CVE.org record CVE-2023-42793 cve.org
  2. NVD entry CVE-2023-42793 nvd.nist.gov

Government

  1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

  1. jetbrains.com jetbrains.com
  2. blog.jetbrains.com blog.jetbrains.com
  3. packetstormsecurity.com packetstormsecurity.com
  4. attackerkb.com attackerkb.com
  5. securityweek.com securityweek.com
  6. rapid7.com rapid7.com
  7. sonarsource.com sonarsource.com

All exploited JetBrains vulnerabilities · Today’s Security Digest