CVE-2026-68376 (GCVE-0-2026-68376)
Vulnerability from cvelistv5
Published
2026-08-10 12:03
Modified
2026-08-19 16:34
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
sctp: fix auth_hmacs array size in struct sctp_cookie
The auth_hmacs array in struct sctp_cookie is supposed to store a complete
SCTP_AUTH_HMAC_ALGO parameter, which consists of a struct sctp_paramhdr
followed by N HMAC identifiers.
However, the array size was calculated using an extra 2 bytes instead of
sizeof(struct sctp_paramhdr), which is 4 bytes. When four HMAC identifiers
are configured, the HMAC-ALGO parameter stored in the endpoint is larger
than the auth_hmacs buffer in the cookie.
As a result, sctp_association_init() copies beyond the end of auth_hmacs
when initializing the association, corrupting the adjacent auth_chunks
field. This can lead to an invalid HMAC identifier being accepted and later
cause an out-of-bounds read in sctp_auth_get_hmac().
Fix the array size calculation by including the full SCTP parameter header
size.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 1f485649f52929d9937b346a920a522a7363e202 Version: 1f485649f52929d9937b346a920a522a7363e202 Version: 1f485649f52929d9937b346a920a522a7363e202 Version: 1f485649f52929d9937b346a920a522a7363e202 Version: 1f485649f52929d9937b346a920a522a7363e202 Version: 1f485649f52929d9937b346a920a522a7363e202 Version: 1f485649f52929d9937b346a920a522a7363e202 Version: 1f485649f52929d9937b346a920a522a7363e202 |
||
{
"containers": {
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"programFiles": [
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"version": "0",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "5.15.216",
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},
{
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"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.6.148",
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{
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{
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{
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"version": "7.1.6",
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{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"nodes": [
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],
"negate": false,
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix auth_hmacs array size in struct sctp_cookie\n\nThe auth_hmacs array in struct sctp_cookie is supposed to store a complete\nSCTP_AUTH_HMAC_ALGO parameter, which consists of a struct sctp_paramhdr\nfollowed by N HMAC identifiers.\n\nHowever, the array size was calculated using an extra 2 bytes instead of\nsizeof(struct sctp_paramhdr), which is 4 bytes. When four HMAC identifiers\nare configured, the HMAC-ALGO parameter stored in the endpoint is larger\nthan the auth_hmacs buffer in the cookie.\n\nAs a result, sctp_association_init() copies beyond the end of auth_hmacs\nwhen initializing the association, corrupting the adjacent auth_chunks\nfield. This can lead to an invalid HMAC identifier being accepted and later\ncause an out-of-bounds read in sctp_auth_get_hmac().\n\nFix the array size calculation by including the full SCTP parameter header\nsize."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.1,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The out-of-bounds index is taken directly from the `hmac_id` field of an AUTH chunk received from a remote SCTP peer and processed in sctp_sf_eat_auth()/sctp_sf_authenticate(), which is the normal SCTP packet-receive path in net/sctp.\nAC:H - The overflow only occurs when the victim endpoint was configured with exactly four HMAC identifiers via setsockopt(SCTP_HMAC_IDENT); three or fewer fit the buffer exactly. That local socket configuration is beyond a remote attacker\u0027s control, though a local user can arrange it and then attack over loopback.\nPR:N - Once the endpoint is so configured, any peer that completes an ordinary SCTP handshake can send the malformed AUTH chunk; the bogus hmac_id is accepted and dereferenced before any shared-key or HMAC verification, so no credentials of any kind are needed.\nUI:N - The AUTH chunk is consumed automatically by the kernel SCTP state machine on packet receipt; no action by any local user or administrator is needed at attack time.\nS:U - The corruption and the subsequent out-of-bounds accesses are confined to kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - sctp_auth_get_hmac() reads far past the 4-entry sctp_hmac_list, and on kernels before the HMAC library conversion sctp_auth_calculate_hmac() reads a function-table pointer ~262 KB beyond the 4-pointer ep-\u003eauth_hmacs heap array; the accepted/rejected signature length acts as an oracle leaking the out-of-bounds value.\nI:H - The wild crypto_shash pointer fetched out of bounds is passed straight to crypto_shash_setkey()/crypto_shash_tfm_digest(), giving an attacker-groomable indirect call and write target; on current kernels a fixed 32-byte HMAC is written into a digest area sized from out-of-bounds data.\nA:H - Dereferencing an out-of-bounds heap pointer as a crypto transform, or writing a 32-byte digest into an undersized skb region, reliably oopses or panics the kernel, and the attack can be repeated on every association."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:34:35.759Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/317731d01b03c529809df36d3a7d149677a8729d"
},
{
"url": "https://git.kernel.org/stable/c/0528485f27016a42804abe01aa61b39d85fa803e"
},
{
"url": "https://git.kernel.org/stable/c/ee5e65964f456adfe14d526fba0bd055de98ecf3"
},
{
"url": "https://git.kernel.org/stable/c/0b4414e43e0861d67276031cc21401d7e87de3da"
},
{
"url": "https://git.kernel.org/stable/c/d0a59ba58578e2b330fff80a44fe519f3ba7d8c7"
},
{
"url": "https://git.kernel.org/stable/c/a8d20ba0ab518c9ccbcde258f25fc1ee6e51d5db"
},
{
"url": "https://git.kernel.org/stable/c/3aa40c3bccac2312ea7cf97f329190637f972b5d"
},
{
"url": "https://git.kernel.org/stable/c/e0b5252a59383b77d1b8dbeda00b7184dd95f4d3"
}
],
"title": "sctp: fix auth_hmacs array size in struct sctp_cookie",
"x_generator": {
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}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68376",
"datePublished": "2026-08-10T12:03:54.666Z",
"dateReserved": "2026-07-30T09:28:09.386Z",
"dateUpdated": "2026-08-19T16:34:35.759Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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