The TCP protocol in RFC 9293 has a timing side channel that makes it easier for remote…
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Will not fix Red Hat: no fix planned
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
The TCP protocol in RFC 9293 has a timing side channel that makes it easier for remote attackers to infer the content of one TCP connection from a client system (to any server), when that client system is concurrently obtaining TCP data at a slow rate from an attacker-controlled server, aka the "SnailLoad" issue. For example, the attack can begin by measuring RTTs via the TCP segments whose role is to provide an ACK control bit and an Acknowledgment Number.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 9 | Affected | No fix planned: Will not fix |
Timeline
- 2026-10-02 Threatist record created from CVE-2024-39920
- 2026-10-03 Alias added: GHSA-796p-jr7h-8vmq
References
Other 8
- https://www.snailload.com
- https://www.snailload.com/snailload.pdf
- https://github.com/IAIK/SnailLoad
- https://www.rfc-editor.org/rfc/rfc9293.txt
- https://www.tugraz.at/en/tu-graz/services/news-stories/tu-graz-news/singleview/article/neue-sicherheitsluecke-erlaubt-ueberwachung-besuchter-websites-und-angesehener-videos
- https://twitter.com/tugraz/status/1805272833322299412
- https://news.ycombinator.com/item?id=40809629
- https://www.instagram.com/p/C8wpO1UtExw/
Sources
- CVE-2024-39920 · CVE Program
- CVE-2024-39920 · NVD
- FIRST EPSS
- GHSA-796p-jr7h-8vmq · GitHub Advisory Database · CC BY 4.0
- CVE-2024-39920 · Red Hat security data · CC BY 4.0
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