RDMA/siw: Reject MPA FPDU length underflow before signed receive math
In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Reject MPA FPDU length underflow before signed receive math A malicious connected siw peer can send an iWARP FPDU whose MPA length field (c_hdr->mpa_len, 16 bit big-endian, peer-controlled) is smaller than the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP parses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode] .hdr_len, but never compares mpa_len against that header length. siw_tcp_rx_data() then derives srx->fpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd + MPA_HDR_SIZE; where fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this point. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest on-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below hdr_len - MPA_HDR_SIZE underflows to a negative int. The signed value then flows into siw_proc_write()/siw_proc_rresp() as bytes = min(srx->fpdu_part_rem, srx->skb_new); is handed to siw_check_mem() as an int len (whose interval check addr + len > mem->va + mem->len is satisfied for a valid base when len is negative), and reaches siw_rx_data() -> siw_rx_kva() / siw_rx_umem() -> skb_copy_bits() as a signed copy length. The header copy branch in skb_copy_bits() promotes that to size_t, producing a multi-gigabyte read. KASAN under a KUnit harness that drives the real kernel TCP receive path -- a loopback AF_INET socketpair, the malformed FPDU written via kernel_sendmsg, sk_data_ready firing in softi
CVE-2026-64102
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64102
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "683f7cfbf514193d63c0efa079f3352bde84c2e0",
"versionType": "git"
},
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "4a331582011d9e8089af8aa2a61ec6b4443bb245",
"versionType": "git"
},
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "33a8b5e971e294ec2a7b74211c545e09efd8e9ac",
"versionType": "git"
},
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "14553be882d9ce91749c9d64041de66e34ad8e70",
"versionType": "git"
},
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "c7c0c0f4379dedec12d24dbb9dded5d2db7fd9f2",
"versionType": "git"
},
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "1012896f4225e8f801ff3c1648023845b66dfb11",
"versionType": "git"
},
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "775b4dc9618a99a1fa48b57554041a5dc17e1336",
"versionType": "git"
},
{
"status": "affected",
"version": "8b6a361b8c482f22ac99c3273285ff16b23fba91",
"lessThan": "0ce1bc9e46ecabe84772bb561e373c0d9876d6f2",
"versionType": "git"
}
],
"programFiles": [
"drivers/infiniband/sw/siw/siw_qp_rx.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.3"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.3",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.258",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.209",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.175",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.142",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.92",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.34",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.11",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/infiniband/sw/siw/siw_qp_rx.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64102
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #40952 · Revision 1
- Added to Heist Feed
- Publisher date