CVE-2026-53263 is a vulnerability in Linux Kernel
Published on June 25, 2026
6lowpan: fix off-by-one in multicast context address compression
In the Linux kernel, the following vulnerability has been resolved:
6lowpan: fix off-by-one in multicast context address compression
The second memcpy in lowpan_iphc_mcast_ctx_addr_compress() uses
&data[1] as destination and &ipaddr->s6_addr[11] as source, but
both should be offset by one: &data[2] and &ipaddr->s6_addr[12]
respectively.
This off-by-one has two consequences:
1. data[1] is overwritten with s6_addr[11], corrupting the RIID
field in the compressed multicast address
2. data[5] is never written, so uninitialized kernel stack memory
is transmitted over the network via lowpan_push_hc_data(),
leaking kernel stack contents
The correct inline data layout must match what the decompression
function lowpan_uncompress_multicast_ctx_daddr() expects:
data[0..1] = s6_addr[1..2] (flags/scope + RIID)
data[2..5] = s6_addr[12..15] (group ID)
Also zero-initialize the data array as a defensive measure against
similar bugs in the future.
Products Associated with CVE-2026-53263
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Affected Versions
Linux:- Version 5609c185f24dffca5f6a9c127106869da150be03 and below f24a58c72a45f4c109f3557a760cc4b60b7a6037 is affected.
- Version 5609c185f24dffca5f6a9c127106869da150be03 and below da8cbb64b47e9066b40af0de170901caf17b768c is affected.
- Version 5609c185f24dffca5f6a9c127106869da150be03 and below 4485d79617520d84ba5a14515e2b5136007d6deb is affected.
- Version 5609c185f24dffca5f6a9c127106869da150be03 and below 06ce6fc106b16dec9b535950db626261be865e5b is affected.
- Version 5609c185f24dffca5f6a9c127106869da150be03 and below dcb1bec1c32ee5c3878354e087cf5dbee2b7c7af is affected.
- Version 5609c185f24dffca5f6a9c127106869da150be03 and below c32f30ef5e66adbfa102348e2e8a23776eb007cb is affected.
- Version 5609c185f24dffca5f6a9c127106869da150be03 and below da8808463882c3f3c357b072e25053c2121f1419 is affected.
- Version 5609c185f24dffca5f6a9c127106869da150be03 and below 2a58899d11009bffc7b4b32a571858f381121837 is affected.
- Version 4.6 is affected.
- Before 4.6 is unaffected.
- Version 5.10.259, <= 5.10.* is unaffected.
- Version 5.15.210, <= 5.15.* is unaffected.
- Version 6.1.176, <= 6.1.* is unaffected.
- Version 6.6.143, <= 6.6.* is unaffected.
- Version 6.12.94, <= 6.12.* is unaffected.
- Version 6.18.36, <= 6.18.* is unaffected.
- Version 7.0.13, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.