CVE-2021-438029.9CriticalCWE-790

CVE-2021-43802: Admin privilege escalation and arbitrary code execution via malicious *.etherpad imports

ether · etherpad-lite

Affected: etherpad-lite · Exploitation: possible (1 to 10%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

2.1%probability of exploitation in the next 30 days

81st percentile

050100

Higher than 81% of scored CVEs

9.9CriticalCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

ether · etherpad-lite< 1.8.16

On the Atlas

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Open the Atlas

Exploitation: Possible (1 to 10%). EPSS between 1% and 10%.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Improper Filtering of Special Elements · Injection and Smuggling
Vendor: ether
Published: December 2021
Band: Possible (1 to 10%), December 2021

CoverageNo articles yet

No CyberSIXT article names CVE-2021-43802 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.