UBUNTU-CVE-2026-90016: Medium severity ubuntu/linux-azure vulnerability
In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix OOB read in rtwrestructwmmie() rtwrestructwmmie() scans inie for a WMM IE with: while (i < inlen) { ... if (i + 5 < inlen && inie[i] == 0xDD && ...) { ... break; } i += (inie[i + 1] + 2); / to the next IE element / } When the "i + 5 < inlen" match check fails simply because i is within 5 bytes of the end of the buffer (i.e. no WMM IE was found near the tail of inie), execution falls through to "i += (inie[i + 1] + 2)", which reads inie[i + 1]. If i == inlen - 1 at that point, this is a 1-byte out-of-bounds read of an attacker-influenced IE buffer built from association/scan data. Commit a75281626fc8f ("staging: rtl8723bs: fix potential out-of-bounds read in rtwrestructwmmie") added the "i + 5 < inlen" guard to the match condition itself, but did not add an equivalent guard before the fallthrough advance, so the same class of OOB read remained reachable through the non-matching path. Add an explicit bounds check before advancing to the next IE.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
Add an explicit bounds check before advancing to the next IE in rtw_restruct_wmm_ie(), guarding the read of in_ie[i + 1] when the WMM match condition fails near the end of in_ie.
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using the affected Ubuntu kernel packages are exposed when the staging rtl8723bs wireless driver processes attacker-influenced association or scan information elements. The listed packages include Ubuntu linux, linux-azure, linux-aws-fips, linux-azure-fips, linux-fips, linux-gcp-fips, linux-gcp, and linux-oracle.
What does an attacker need to exploit the flaw?
An attacker needs to provide crafted wireless association or scan data containing information elements that reach rtw_restruct_wmm_ie(). No attacker privileges are required, but user interaction is required according to the supplied severity vector.
How can I determine whether a system may be affected?
Determine whether the system is running one of the listed Ubuntu kernel packages and uses the staging rtl8723bs driver. The vulnerable path is reached while that driver parses wireless association or scan data, particularly when an information-element buffer ends with a non-matching trailing byte.