How severe is CVE-2026-74310?

CVE-2026-74310 has a CVSS score of 9.3/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-74310?

CVE-2026-74310 affects the following packages: Kernel (Linux). Ecosystems affected: Linux.

How do I fix CVE-2026-74310?

Update Kernel to 6.1.178 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-74310 is resolved across your whole dependency graph.

How do I detect CVE-2026-74310 in my Linux dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-74310 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-74310?

O3 pinpoints whether CVE-2026-74310 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-74310 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-74310 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-74310 published, and has it been updated?

CVE-2026-74310 was published on August 15, 2026 and was last updated on August 18, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐧

🐧 Linux

Not in CISA KEV

CRITICAL severity

CVE-2026-74310

CRITICAL

CVE-2026-74310 is a critical-severity (CVSS 9.3) vulnerability in Kernel. O3 Security confirms whether CVE-2026-74310 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

vhost/net: complete zerocopy ubufs only once

Published

Aug 15, 2026

Updated

Aug 18, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐧Kernel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.

Description

In the Linux kernel, the following vulnerability has been resolved:

vhost/net: complete zerocopy ubufs only once

vhost-net initializes one ubuf_info per outstanding zerocopy TX descriptor and hands it to the backend socket. The networking stack may then clone a zerocopy skb before all skb references are released. For example, batman-adv fragmentation reaches skb_split(), which calls skb_zerocopy_clone() and increments the same ubuf_info refcount.

vhost_zerocopy_complete() currently treats every ubuf callback as a completed vhost descriptor. It dereferences ubuf->ctx, writes the descriptor completion state, and drops the vhost_net_ubuf_ref even when the callback only releases a cloned skb reference. A backend reset can therefore wait for and free the vhost_net_ubuf_ref while another cloned skb still carries the same ubuf_info. A later completion then dereferences the freed ubufs pointer.

KASAN reports the stale completion as:

BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0 BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0 vhost_zerocopy_complete skb_copy_ubufs __dev_forward_skb2 veth_xmit

The freed object was allocated from vhost_net_ioctl() while setting the backend and freed through kfree_rcu()/kvfree_rcu_bulk after backend removal, while delayed skb completion still reached vhost_zerocopy_complete().

Honor the generic ubuf_info refcount before touching vhost state, and run the vhost descriptor completion only for the final ubuf reference. This matches the msg_zerocopy_complete() ownership rule for cloned zerocopy skbs.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐧Linux	`Kernel`	≥ 3.1.0&&< 6.1.178	6.1.178

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Kernel to 6.1.178 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-74310 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-74310 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-74310. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In the Linux kernel, the following vulnerability has been resolved: vhost/net: complete zerocopy ubufs only once vhost-net initializes one ubuf_info per outstanding zerocopy TX descriptor and hands it to the backend socket. The networking stack may then clone a zerocopy skb before all skb references are released. For example, batman-adv fragmentation reaches skb_split(), which calls skb_zerocopy_clone() and increments the same ubuf_info refcount. vhost_zerocopy_complete() currently treats every ubuf callback as a completed vhost descriptor. It dereferences ubuf->ctx, writes the descripto

O3 Security · Impact-Aware SCA

Is CVE-2026-74310 in your dependencies?

O3 detects CVE-2026-74310 across Linux dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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