CVE-2026-74705 udp: fix potential use-after-free in tunnel segmentation
Critical 10.0
Published
Updated
Check this codebase for CVE-2026-74705 and fix it if it is affected.
What it is: CVE-2026-74705 is a critical use after free vulnerability in Linux, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74705 in the wild and no public exploit code.
Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-74705/ (Markdown: https://insights.sbomify.com/CVE-2026-74705/index.md)
A use-after-free in Linux kernel UDP tunnel segmentation allows attackers to potentially execute code or escalate privileges.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74705?
CVE-2026-74705 is a critical use after free vulnerability in Linux, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
udp: fix potential use-after-free in tunnel segmentation
__skb_udp_tunnel_segment() gets the UDP header before ensuring the tunnel header is in the skb head. If the pull reallocates skb->head, the saved UDP header pointer is no longer valid.
Get the UDP header after the pull to avoid a potential use-after-free.
Which versions are affected by CVE-2026-74705?
Linux distribution packages (40)
bpftool-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:7.3.0-427.155.1.el9_4 |
kernel-64k-debug-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debug-devel Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debug-devel-matched Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-devel Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-devel-matched Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debug-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debug-devel Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debug-devel-matched Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debuginfo-common-aarch64 Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debuginfo-common-ppc64le Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debuginfo-common-s390x Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-debuginfo-common-x86_64 Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-devel Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-devel-matched Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-doc Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-rt-debug-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-rt-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-tools-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-zfcpdump-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-zfcpdump-devel Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-zfcpdump-devel-matched Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
libperf-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
perf Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
perf-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
python3-perf-debuginfo Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
rtla Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
rv Red Hat:rhel_e4s:9.4::appstream | All versions | 0:5.14.0-427.155.1.el9_4 |
bpftool Red Hat:rhel_e4s:9.4::baseos | All versions | 0:7.3.0-427.155.1.el9_4 |
bpftool-debuginfo Red Hat:rhel_e4s:9.4::baseos | All versions | 0:7.3.0-427.155.1.el9_4 |
kernel Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-core Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debug Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debug-core Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debug-debuginfo Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debug-modules Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
kernel-64k-debug-modules-core Red Hat:rhel_e4s:9.4::baseos | All versions | 0:5.14.0-427.155.1.el9_4 |
How do I fix CVE-2026-74705?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-74705 being exploited?
There is no known exploitation of CVE-2026-74705 in the wild and no public exploit code.
Sources
Also known as AZL-97182, BELL-CVE-2026-74705, DEBIAN-CVE-2026-74705, GHSA-rcm8-q4cm-988v, RHSA-2026:79784, RHSA-2026:79786 and 1 more.