Information Exposure Affecting linux-5.10 package, versions <5.10.178-3~deb10u1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

Exploit Maturity
Mature
EPSS
0.1% (42nd percentile)

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  • Snyk IDSNYK-DEBIAN10-LINUX510-5489465
  • published13 Apr 2023
  • disclosed21 Apr 2023

Introduced: 13 Apr 2023

CVE-2023-1998  (opens in a new tab)
CWE-203  (opens in a new tab)

How to fix?

Upgrade Debian:10 linux-5.10 to version 5.10.178-3~deb10u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-5.10 package and not the linux-5.10 package as distributed by Debian. See How to fix? for Debian:10 relevant fixed versions and status.

The Linux kernel allows userspace processes to enable mitigations by calling prctl with PR_SET_SPECULATION_CTRL which disables the speculation feature as well as by using seccomp. We had noticed that on VMs of at least one major cloud provider, the kernel still left the victim process exposed to attacks in some cases even after enabling the spectre-BTI mitigation with prctl. The same behavior can be observed on a bare-metal machine when forcing the mitigation to IBRS on boot command line.

This happened because when plain IBRS was enabled (not enhanced IBRS), the kernel had some logic that determined that STIBP was not needed. The IBRS bit implicitly protects against cross-thread branch target injection. However, with legacy IBRS, the IBRS bit was cleared on returning to userspace, due to performance reasons, which disabled the implicit STIBP and left userspace threads vulnerable to cross-thread branch target injection against which STIBP protects.

CVSS Scores

version 3.1