Bug 2467064 (CVE-2026-43190) - CVE-2026-43190 kernel: netfilter: xt_tcpmss: check remaining length before reading optlen
Summary: CVE-2026-43190 kernel: netfilter: xt_tcpmss: check remaining length before re...
Keywords:
Status: NEW
Alias: CVE-2026-43190
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-06 13:02 UTC by OSIDB Bzimport
Modified: 2026-05-06 20:42 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-05-06 13:02:19 UTC
In the Linux kernel, the following vulnerability has been resolved:

netfilter: xt_tcpmss: check remaining length before reading optlen

Quoting reporter:
  In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads
 op[i+1] directly without validating the remaining option length.

  If the last byte of the option field is not EOL/NOP (0/1), the code attempts
  to index op[i+1]. In the case where i + 1 == optlen, this causes an
  out-of-bounds read, accessing memory past the optlen boundary
  (either reading beyond the stack buffer _opt or the
  following payload).


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