CVE-2026-53003pppoe: drop PFC frames
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Analyzed
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 before cb3beef35ab5e0c1afca9fd7648c6ae499786377; from 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 before ba758fdf1399f310b30098b6faa3fd043de47dd2; from 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 before fcca1df05322bb04e344dd1178b54b76a08eb7c3; from 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 before 8a5e840babc5c0fbd10c73728a13192347771ec6; from 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 before 49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71; 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 builds before 0cab5d077dd1efd2bd1a47271acc35894f945b4f; 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 builds before 2b5c3c040d020e3ab3b9a8887031202d96843b1e; from 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6 before cc1ff87bce1ccd38410ab10960f576dcd17db679 | CNA record |
linux linux_kernel linux:linux_kernel | from 5.0 before 5.10.258; from 5.11 before 5.15.209; from 5.16 before 6.1.175; from 6.2 before 6.6.141; from 6.7 before 6.12.91; from 6.13 before 6.18.33; from 6.19 before 7.0.10 | NVD |
References
- https://git.kernel.org/stable/c/cb3beef35ab5e0c1afca9fd7648c6ae499786377patch
- https://git.kernel.org/stable/c/ba758fdf1399f310b30098b6faa3fd043de47dd2patch
- https://git.kernel.org/stable/c/fcca1df05322bb04e344dd1178b54b76a08eb7c3patch
- https://git.kernel.org/stable/c/8a5e840babc5c0fbd10c73728a13192347771ec6patch
- https://git.kernel.org/stable/c/49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71patch
- https://git.kernel.org/stable/c/0cab5d077dd1efd2bd1a47271acc35894f945b4fpatch
- https://git.kernel.org/stable/c/2b5c3c040d020e3ab3b9a8887031202d96843b1epatch
- https://git.kernel.org/stable/c/cc1ff87bce1ccd38410ab10960f576dcd17db679patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.