VulnerabilityPublished 25 Sep 2026Updated 21 Oct 2026

CVE-2026-97997: Linux kernel · virtio_ring: fix stale descriptor flags after a failed packed add

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in d595358276b60e5df4d3930bc94033249b1d5adc : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d595358276b60e5df4d3930bc94033249b1d5adc, cfe8128ceb78374b0f9cebb608bb48e3928d784a, 75d276e5bb68778b2916f98a2bc30f142ebadc64 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 1ce9e6055fa0a9043405c5604cf19169ec5379ff, < d595358276b60e5df4d3930bc94033249b1d5adc	Fixed in d595358276b60e5df4d3930bc94033249b1d5adc
LinuxLinux	Affected ≥ 1ce9e6055fa0a9043405c5604cf19169ec5379ff, < cfe8128ceb78374b0f9cebb608bb48e3928d784a	Fixed in cfe8128ceb78374b0f9cebb608bb48e3928d784a
LinuxLinux	Affected ≥ 1ce9e6055fa0a9043405c5604cf19169ec5379ff, < 75d276e5bb68778b2916f98a2bc30f142ebadc64	Fixed in 75d276e5bb68778b2916f98a2bc30f142ebadc64
LinuxLinux	Affected ≥ 1ce9e6055fa0a9043405c5604cf19169ec5379ff, < 5ad081761a1f0b0d95ab08b61a6008309fba95f9	Fixed in 5ad081761a1f0b0d95ab08b61a6008309fba95f9
LinuxLinux	Affected ≥ 1ce9e6055fa0a9043405c5604cf19169ec5379ff, < 3e6400e3b8b858cdf0f8d70b20d8b55d703af368	Fixed in 3e6400e3b8b858cdf0f8d70b20d8b55d703af368
LinuxLinux	Affected =5.0	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: virtio_ring: fix stale descriptor flags after a failed packed add In a packed ring the AVAIL and USED bits sit in the descriptor itself, so writing them makes that descriptor available. Those bit combinations flip meaning on every round of the ring, tracked by a wrap counter, so invalidating or validating a descriptor means inverting both bits. Commit 1ce9e6055fa0 ("virtio_ring: introduce packed ring support") has virtqueue_add_packed() make every descriptor of a chain available as it maps the chain, and write the head last. The device consumes the ring in order and stops at a head that is not available yet, so it never reaches the rest. When vring_map_one_sg() fails partway, unmap_release unmaps the segments and restores avail_used_flags, but the descriptors it wrote to in the ring stay marked with AVAIL and USED bits. The head is now the only entry that keeps the device from consuming these stale entries. For example, the ring would look like this now. Z - pre-previous command A - previous command B - aborted command C - current command [A1 DONE] [A2 DONE] <C1 EMPTY> [B2] [B3] [Z1 DONE] When the driver now attempts to issue the C command, the next add starts at the same head as B. If C spans less descriptors than B, there is no end marker because AVAIL and USED bits were still in place. And that means the device will start interpreting these stale entries (B2/B3) as another command entry, which then blocks the queue. This effect typically happens in swiotlb configurations under memory pressure, because vring_map_one_sg() can then fail with larger I/O requests which then leads to command abortions. There are broadly 2 ways to avoid leaving those flags behind: 1) Defer those flags too until the chain is complete. 2) Rewrite those flags for the previous wrap counter. Implement the second option in both packed add paths. The first option traverses the chain a second time on every successful add. The second option invalidates all added descriptors when any add fails. With this patch applied, a packed virtqueue keeps completing requests after a failed add.

References

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