CVE-2021-43802

Etherpad is a real-time collaborative editor. In versions prior to 1.8.16, an attacker can craft an `*.etherpad` file that, when imported, might allow the attacker to gain admin privileges for the Etherpad instance. This, in turn, can be used to install a malicious Etherpad plugin that can execute arbitrary code (including system commands). To gain privileges, the attacker must be able to trigger deletion of `express-session` state or wait for old `express-session` state to be cleaned up. Core Etherpad does not delete any `express-session` state, so the only known attacks require either a plugin that can delete session state or a custom cleanup process (such as a cron job that deletes old `sessionstorage:*` records). The problem has been fixed in version 1.8.16. If users cannot upgrade to 1.8.16 or install patches manually, several workarounds are available. Users may configure their reverse proxies to reject requests to `/p/*/import`, which will block all imports, not just `*.etherpad` imports; limit all users to read-only access; and/or prevent the reuse of `express_sid` cookie values that refer to deleted express-session state. More detailed information and general mitigation strategies may be found in the GitHub Security Advisory.
Configurations

Configuration 1 (hide)

cpe:2.3:a:etherpad:etherpad:*:*:*:*:*:*:*:*

History

21 Nov 2024, 06:29

Type Values Removed Values Added
References () https://github.com/ether/etherpad-lite/compare/b7065eb9a0ec7c3c265f8cfeb2534efe6f036456...77bcb507b30e762e9375b0511b3763e0162aae53 - Patch, Third Party Advisory () https://github.com/ether/etherpad-lite/compare/b7065eb9a0ec7c3c265f8cfeb2534efe6f036456...77bcb507b30e762e9375b0511b3763e0162aae53 - Patch, Third Party Advisory
References () https://github.com/ether/etherpad-lite/issues/5010 - Issue Tracking, Third Party Advisory () https://github.com/ether/etherpad-lite/issues/5010 - Issue Tracking, Third Party Advisory
References () https://github.com/ether/etherpad-lite/releases/tag/1.8.16 - Release Notes, Third Party Advisory () https://github.com/ether/etherpad-lite/releases/tag/1.8.16 - Release Notes, Third Party Advisory
References () https://github.com/ether/etherpad-lite/security/advisories/GHSA-w3g3-qf3g-2mqc - Mitigation, Patch, Third Party Advisory () https://github.com/ether/etherpad-lite/security/advisories/GHSA-w3g3-qf3g-2mqc - Mitigation, Patch, Third Party Advisory
CVSS v2 : 9.0
v3 : 8.8
v2 : 9.0
v3 : 9.9

31 Aug 2023, 16:19

Type Values Removed Values Added
CWE NVD-CWE-Other

Information

Published : 2021-12-09 23:15

Updated : 2024-11-21 06:29


NVD link : CVE-2021-43802

Mitre link : CVE-2021-43802

CVE.ORG link : CVE-2021-43802


JSON object : View

Products Affected

etherpad

  • etherpad
CWE
CWE-790

Improper Filtering of Special Elements

CWE-1287

Improper Validation of Specified Type of Input

CWE-20

Improper Input Validation

NVD-CWE-Other