Bug 2521287

Summary: CVE-2026-77639 tor: Tor: Denial of Service via compression bomb bypass [fedora-all]
Product: [Fedora] Fedora Reporter: Vladimir Vasilev <vvasilev>
Component: torAssignee: Marcel Haerry <mh>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: mh, pablo, paul.wouters, rh-bugzilla
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["556205cd-c395-4a14-a0e1-451bd382d234"]}
Fixed In Version: tor-0.4.9.14-1.fc44 tor-0.4.9.14-1.fc43 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-10-17 01:05:50 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2520794    

Description Vladimir Vasilev 2026-08-22 11:47:48 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Tor before 0.4.9.9 was prone to a compression bomb bypass where an attacker could concatenate many gzip or zlib sub-streams, each just under the per-stream detection threshold, to avoid the compression bomb check entirely. This is TROVE-2026-022.

Comment 1 Fedora Update System 2026-10-08 13:42:00 UTC
FEDORA-2026-bfe95c54ee (tor-0.4.9.14-1.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-bfe95c54ee

Comment 2 Fedora Update System 2026-10-08 13:42:12 UTC
FEDORA-2026-f51af3db87 (tor-0.4.9.14-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-f51af3db87

Comment 3 Fedora Update System 2026-10-08 13:42:23 UTC
FEDORA-2026-8a3e460f1e (tor-0.4.9.14-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-8a3e460f1e

Comment 4 Fedora Update System 2026-10-09 02:08:38 UTC
FEDORA-2026-bfe95c54ee has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-bfe95c54ee`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-bfe95c54ee

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 5 Fedora Update System 2026-10-09 02:30:32 UTC
FEDORA-2026-f51af3db87 has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-f51af3db87`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-f51af3db87

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 6 Fedora Update System 2026-10-09 02:55:27 UTC
FEDORA-2026-8a3e460f1e has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-8a3e460f1e`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-8a3e460f1e

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 7 Fedora Update System 2026-10-17 01:05:50 UTC
FEDORA-2026-f51af3db87 (tor-0.4.9.14-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 8 Fedora Update System 2026-10-17 01:32:38 UTC
FEDORA-2026-8a3e460f1e (tor-0.4.9.14-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.