libpcap: Fix CVE-2026-31911

NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31911
Upstream-commit: https://github.com/the-tcpdump-group/libpcap/commit/a715bcdde830299cba4171514385cb17ec19b6e9

(From OE-Core rev: 26ada8f7dd521e6b472078b2dac57e0e0f635048)

Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Paul Barker <paul@pbarker.dev>

meta/recipes-connectivity/libpcap/libpcap/03-CVE-2026-31911.patch

@@ -0,0 +1,47 @@
+From a715bcdde830299cba4171514385cb17ec19b6e9 Mon Sep 17 00:00:00 2001
+From: Denis Ovsienko <denis@ovsienko.info>
+Date: Thu, 30 Jul 2026 13:34:08 +0100
+Subject: [PATCH] CVE-2026-31911: Fail opcodes safely in the BPF interpreter.
+
+This vulnerability has been discovered by FuzzAnything Organization.
+
+The current revision of pcapint_filter_with_aux_data() calls abort() if
+the current instruction opcode is invalid, and assumes this never to be
+the case.  This holds for programs that have been generated by libpcap.
+
+However, this does not necessarily hold for programs that come from an
+external source via pcap_offline_filter() or [deprecated] bpf_filter().
+Furthermore, this does not necessarily hold for programs that have been
+validated by libpcap because the current revision of the validator has
+gaps in the checks and accepts a number of invalid opcodes (another
+commit addresses that).
+
+Thus in pcapint_filter_with_aux_data(), when the instruction opcode is
+invalid, just reject the packet.
+
+(backported from commit 4ccb54bf4946d31a248ec93bdbeaabd97fb9d8f7)
+
+(cherry picked from commit a715bcdde830299cba4171514385cb17ec19b6e9)
+
+Notes on backporting to 1.10.4:
+ - Adapted to the 1.10.4 pcap_filter*() names (renamed to pcapint_*()
+   after 1.10.4).
+ - The upstream CHANGES/changelog hunk is not backported.
+
+Upstream-Status: Backport [https://github.com/the-tcpdump-group/libpcap/commit/a715bcdde830299cba4171514385cb17ec19b6e9]
+CVE: CVE-2026-31911
+Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
+---
+diff --git a/bpf_filter.c b/bpf_filter.c
+index 2ea11d46..d6e4b019 100644
+--- a/bpf_filter.c
++++ b/bpf_filter.c
+@@ -146,7 +146,7 @@ pcap_filter_with_aux_data(const struct bpf_insn *pc, const u_int proglen,
+ 		switch (pc->code) {
+ 
+ 		default:
+-			abort();
++			return 0;
+ 		case BPF_RET|BPF_K:
+ 			return (u_int)pc->k;
+ 

meta/recipes-connectivity/libpcap/libpcap_1.10.4.bb

@@ -19,6 +19,7 @@ SRC_URI = "https://www.tcpdump.org/release/${BP}.tar.gz \
            file://CVE-2025-11964.patch \
            file://01-CVE-2026-0799.patch \
            file://02-CVE-2026-31912.patch \
+           file://03-CVE-2026-31911.patch \
           "
 
 SRC_URI[sha256sum] = "ed19a0383fad72e3ad435fd239d7cd80d64916b87269550159d20e47160ebe5f"