Improper Handling of Length Parameter Inconsistency Affecting bpftool-debuginfo package, versions <1:6.1.168-202.320.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.02% (4th percentile)

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  • Snyk IDSNYK-AMZN2023-BPFTOOLDEBUGINFO-16625657
  • published10 May 2026
  • disclosed26 Mar 2026

Introduced: 26 Mar 2026

CVE-2026-23397  (opens in a new tab)
CWE-130  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 bpftool-debuginfo to version 1:6.1.168-202.320.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1681.

NVD Description

Note: Versions mentioned in the description apply only to the upstream bpftool-debuginfo package and not the bpftool-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

nfnetlink_osf: validate individual option lengths in fingerprints

nfnl_osf_add_callback() validates opt_num bounds and string NUL-termination but does not check individual option length fields. A zero-length option causes nf_osf_match_one() to enter the option matching loop even when foptsize sums to zero, which matches packets with no TCP options where ctx->optp is NULL:

Oops: general protection fault KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98) Call Trace: nf_osf_match (net/netfilter/nfnetlink_osf.c:227) xt_osf_match_packet (net/netfilter/xt_osf.c:32) ipt_do_table (net/ipv4/netfilter/ip_tables.c:293) nf_hook_slow (net/netfilter/core.c:623) ip_local_deliver (net/ipv4/ip_input.c:262) ip_rcv (net/ipv4/ip_input.c:573)

Additionally, an MSS option (kind=2) with length < 4 causes out-of-bounds reads when nf_osf_match_one() unconditionally accesses optp[2] and optp[3] for MSS value extraction. While RFC 9293 section 3.2 specifies that the MSS option is always exactly 4 bytes (Kind=2, Length=4), the check uses "< 4" rather than "!= 4" because lengths greater than 4 do not cause memory safety issues -- the buffer is guaranteed to be at least foptsize bytes by the ctx->optsize == foptsize check.

Reject fingerprints where any option has zero length, or where an MSS option has length less than 4, at add time rather than trusting these values in the packet matching hot path.

CVSS Base Scores

version 3.1