CVE-2026-45890: Linux kernel · xen-netback: reject zero-queue configuration from guest
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 May 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.
Description
In the Linux kernel, the following vulnerability has been resolved: xen-netback: reject zero-queue configuration from guest A malicious or buggy Xen guest can write "0" to the xenbus key "multi-queue-num-queues". The connect() function in the backend only validates the upper bound (requested_num_queues > xenvif_max_queues) but not zero, allowing requested_num_queues=0 to reach vzalloc(array_size(0, sizeof(struct xenvif_queue))), which triggers WARN_ON_ONCE(!size) in __vmalloc_node_range(). On systems with panic_on_warn=1, this allows a guest-to-host denial of service. The Xen network interface specification requires the queue count to be "greater than zero". Add a zero check to match the validation already present in xen-blkback, which has included this guard since its multi-queue support was added.
References
- nvd.nist.gov/vuln/detail/CVE-2026-45890 (opens in a new tab)
- git.kernel.org/stable/c/2993e0f904c45f8af12917344bb1cac7ccd05a60 (opens in a new tab)
- git.kernel.org/stable/c/654780dee9eae419e1648ea58462c4efe54518fa (opens in a new tab)
- git.kernel.org/stable/c/6d1dc8014334c7fb25719999bca84d811e60a559 (opens in a new tab)
- git.kernel.org/stable/c/787bfa423228c4b02ba3368128f625d579085353 (opens in a new tab)
- git.kernel.org/stable/c/88b0fced1bbbfdb356a007592604008ffc93a6a1 (opens in a new tab)
- git.kernel.org/stable/c/ce66d6786de45b7ed9cbbdc0988054bf09e58f54 (opens in a new tab)
- git.kernel.org/stable/c/d99f69ddc70fd9f4b8148add62209a1a8eb5c615 (opens in a new tab)
- git.kernel.org/stable/c/ec4859ac5c933e3315543a61adc1ca4358006a41 (opens in a new tab)