CVE-2026-19735

The Zephyr TCP stack contains a vulnerability where the RFC 6528 initial-sequence-number (ISN) implementation may use predictable values. If the sys_csrand_get() call fails during early boot (e.g., due to -ENODEV or -EIO from the entropy driver), the system fails to catch the error and leaves the...

CVE-2026-19735 Predictable TCP initial sequence numbers when the RFC 6528 secret key generation fails silently in the Zephyr TCP stack

The RFC 6528 initial-sequence-number implementation in subsys/net/ip/tcp.c derived every TCP ISN from SHA-256uniquekey || four-tuple plus a uptime-derived offset, where uniquekey is a 128-bit secret filled once by syscsrandget. The return value of that call was discarded and the once guard was...

CVE-2026-19577 Out-of-bounds read in IPv6 route forwarding when the nexthop neighbor has no link-layer address

netrouteipv6packet in subsys/net/ip/routeipv6.c resolved the nexthop's link-layer address with netnbrgetlladdrnbr-idx without first checking whether the neighbor cache entry actually had a linked link-layer address. An unresolved neighbor carries idx == NETNBRLLADDRUNKNOWN 0xff, and netnbrgetllad...

CVE-2026-16515 ICMPv6 error messages sent for multicast-destined packets and non-unique source addresses enable network amplification in Zephyr's IPv6 stack

neticmpv6senderror in subsys/net/ip/icmpv6.c implemented only one of the three RFC 4443 section 2.4 suppression rules do not answer an ICMPv6 error with an ICMPv6 error. It did not check whether the triggering packet's source address identifies a single node rule e.6 or whether the packet was sen...

CVE-2026-16515: Insufficient Control of Network Message Volume (Network Amplification)

neticmpv6senderror in subsys/net/ip/icmpv6.c implemented only one of the three RFC 4443 section 2.4 suppression rules do not answer an ICMPv6 error with an ICMPv6 error. It did not check whether the triggering packet's source address identifies a single node rule e.6 or whether the packet was sen...

PT-2026-95410

Name of the Vulnerable Software and Affected Versions Zephyr affected versions not specified Description The net icmpv6 send error function in subsys/net/ip/icmpv6.c fails to implement all RFC 4443 section 2.4 suppression rules, which dictate that an ICMPv6 error should not be answered with anoth...

CVE-2026-15893: Reachable Assertion

netifipv6calcreachabletime in subsys/net/ip/netif.c derives a randomized ND reachable time from ipv6-basereachabletime as minreachable + sysrand32get % maxreachable - minreachable, where minreachable = base/2 and maxreachable = 3base/2 using integer division. When basereachabletime is 1, both...

CVE-2026-12630: Out-of-bounds Read

Zephyr's 6LoWPAN IP Header Compression IPHC uncompression code contains an out-of-bounds read in getihpcinlinedsize subsys/net/ip/6lo.c. The destination inline size is looked up in dainlinesizetable, which has 13 entries, using an index built from the M, DAC and DAM bits of the received IPHC...

CVE-2026-10686: Loop with Unreachable Exit Condition

Zephyr's IPv6 forwarding path re-sent routed unicast packets without ever decrementing the IPv6 hop limit. Both routing branches of ipv6routepacket subsys/net/ip were affected: the explicit-route path netroutepacket and the on-link cross-interface path netroutepacketif. Each set the packet...

CVE-2026-7656: Authentication Bypass by Spoofing

The IPv6 Neighbor Discovery handlers in subsys/net/ip/ipv6nbr.c handlerainput, handlensinput, handlenainput used an incorrect boolean expression that combined the RFC 4861 validity checks with the ICMPv6 code check using the wrong operator precedence: the form was length/hop/source/target checks ...

CVE-2026-10637: Use After Free

subsys/net/ip/ipv6mld.c:mldsend read the packet interface via netpktifacepkt after netsenddatapkt returned successfully. Per the network stack's ownership contract include/zephyr/net/netcore.h, and the explicit warning in subsys/net/ip/netcore.c:453-460 'do not use pkt after that call', a...

Out-of-bounds

In subsys/net/ip/tcp.c , function tcpflags , when the incoming parameter flags is ECN or CWR , the buf will out-of-bounds write a byte zero...

CVE-2022-1841 Out-of-bound write in tcp_flags

In subsys/net/ip/tcp.c , function tcpflags , when the incoming parameter flags is ECN or CWR , the buf will out-of-bounds write a byte zero...

CVE-2022-1841

In subsys/net/ip/tcp.c , function tcpflags , when the incoming parameter flags is ECN or CWR , the buf will out-of-bounds write a byte zero...

CVE-2022-1841: Out-of-bounds Write

In subsys/net/ip/tcp.c , function tcpflags , when the incoming parameter flags is ECN or CWR , the buf will out-of-bounds write a byte zero...