CVE-2019-18805 — An issue was discovered in net/ipv4/sysctl_net_ipv4

An issue was discovered in net/ipv4/sysctl_net_ipv4.c in the Linux kernel before 5.0.11. There is a net/ipv4/tcp_input.c signed integer overflow in tcp_ack_update_rtt() when userspace writes a very large integer to /proc/sys/net/ipv4/tcp_min_rtt_wlen, leading to a denial of servi

01What is this vulnerability?

An issue was discovered in net/ipv4/sysctl_net_ipv4.c in the Linux kernel before 5.0.11. There is a net/ipv4/tcp_input.c signed integer overflow in tcp_ack_update_rtt() when userspace writes a very large integer to /proc/sys/net/ipv4/tcp_min_rtt_wlen, leading to a denial of service or possibly unspecified other impact, aka CID-19fad20d15a6.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-11-07T13:08:05.000Z
• Last modified: 2024-08-05T02:02:39.538Z

09References

• cdn.kernel.org — https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.0.11
• git.kernel.org — https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=19…
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00035.html
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00039.html
• security.netapp.com — https://security.netapp.com/advisory/ntap-20191205-0001/
• access.redhat.com — https://access.redhat.com/errata/RHSA-2020:0740