CVE-2026-53003pppoe: drop PFC frames
- 7.5HighCVSS base score
- 0.72%Exploitation in 30 daysEPSS · top 46% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: pppoe: drop PFC frames RFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT RECOMMENDED for PPPoE. In practice, pppd does not support negotiating PFC for PPPoE sessions, and the current PPPoE driver assumes an uncompressed (2-byte) protocol field. However, the generic PPP layer function ppp_input() is not aware of the negotiation result, and still accepts PFC frames. If a peer with a broken implementation or an attacker sends a frame with a compressed (1-byte) protocol field, the subsequent PPP payload is shifted by one byte. This causes the network header to be 4-byte misaligned, which may trigger unaligned access exceptions on some architectures. To reduce the attack surface, drop PPPoE PFC frames. Introduce ppp_skb_is_compressed_proto() helper function to be used in both ppp_generic.c and pppoe.c to avoid open-coding.
Timeline
ID reserved
By Linux
- 15 days later
· 15 days later
Published
- 4 months later
· 4 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.72% · top 46% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < cb3beef35ab5e0c1afca9fd7648c6ae499786377
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < ba758fdf1399f310b30098b6faa3fd043de47dd2
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < fcca1df05322bb04e344dd1178b54b76a08eb7c3
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < 8a5e840babc5c0fbd10c73728a13192347771ec6
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < 49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < 0cab5d077dd1efd2bd1a47271acc35894f945b4f
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < 2b5c3c040d020e3ab3b9a8887031202d96843b1e
- affected 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 – < cc1ff87bce1ccd38410ab10960f576dcd17db679
- affected 5.0
- unaffected < 5.0
- unaffected 5.10.258 – ≤ 5.10.*
- unaffected 5.15.209 – ≤ 5.15.*
- unaffected 6.1.175 – ≤ 6.1.*
- unaffected 6.6.141 – ≤ 6.6.*
- unaffected 6.12.91 – ≤ 6.12.*
- unaffected 6.18.33 – ≤ 6.18.*
- unaffected 7.0.10 – ≤ 7.0.*
- unaffected 7.1 – ≤ *
References
References8
- https://git.kernel.org/stable/c/cb3beef35ab5e0c1afca9fd7648c6ae499786377 (opens in a new tab)
- https://git.kernel.org/stable/c/ba758fdf1399f310b30098b6faa3fd043de47dd2 (opens in a new tab)
- https://git.kernel.org/stable/c/fcca1df05322bb04e344dd1178b54b76a08eb7c3 (opens in a new tab)
- https://git.kernel.org/stable/c/8a5e840babc5c0fbd10c73728a13192347771ec6 (opens in a new tab)
- https://git.kernel.org/stable/c/49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71 (opens in a new tab)
- https://git.kernel.org/stable/c/0cab5d077dd1efd2bd1a47271acc35894f945b4f (opens in a new tab)
- https://git.kernel.org/stable/c/2b5c3c040d020e3ab3b9a8887031202d96843b1e (opens in a new tab)
- https://git.kernel.org/stable/c/cc1ff87bce1ccd38410ab10960f576dcd17db679 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-38871 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-53003)Record last updated .