Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes
Linux · Linux kernel
The Linux kernel's TCP stack hard-codes its default maximum segment size (MSS) to 48 bytes, which causes TCP resend queues to be fragmented far more than a larger enforced MSS would. A remote peer with network access can exploit this without authentication or user interaction to cause a denial of service.
Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.
- Exploited
- Not confirmed
- Reports
- 0
- Tactics
- 0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
Disclosed on 18 Jun 2019. No public exploit code or confirmed exploitation is recorded.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linkedNo ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.
What security researchers reported
Not named in any threat report yetAlso mentioned in 1 community threat pulse (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Denial-of-service attack - Wikipedia8 Jun 2022