CVE-2021-40438

high KEV

Published 2021-12-01 · Modified 2021-12-01

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CVSS v3

—

CVSS v4 NEW

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not yet in upstream

VIR risk

9.5

Description

A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.

CISA KEV

Vendor: Apache
Product: Apache
Due date: 2021-12-15

Predictions

Exploit likelihood

99%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

Exploits

Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.

OS impact

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

AlmaLinux Fixed 1 release

Version	Status	Fixed in
8	Fixed	`mod_md-2.0.8-8.module_el8.6.0+2872+fe0ff7aa.aarch64.rpm`

Arch Fixed 1 release

Version	Status	Fixed in
—	Fixed	`2.4.49-1`

Debian Fixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`2.4.49-1`
sid	Fixed	`2.4.49-1`
forky	Fixed	`2.4.49-1`
bullseye	Fixed	`2.4.51-1~deb11u1`
bookworm	Fixed	`2.4.49-1`

Red Hat Fixed 1 release

Version	Status	Fixed in
8	Fixed	—

Rocky Linux Fixed 1 release

Version	Status	Fixed in
8	Fixed	—

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.