In the Linux kernel, the following vulnerability has been resolved:
binder: cache secctx size before release zeroes it
binder_transaction() bounds the scatter-gather buffer area with
sg_buf_end_offset and subtracts the aligned LSM context size because
the secctx is written at the tail of that area. The subtraction reads
lsmctx.len, but that field has already been cleared by the time the
line runs:
security_secid_to_secctx(secid, &lsmctx) /* lsmctx.len set */
lsmctx_aligned_size = ALIGN(lsmctx.len, sizeof(u64))
extra_buffers_size += lsmctx_aligned_size
...
security_release_secctx(&lsmctx) /* memset zeroes len */
...
sg_buf_end_offset = sg_buf_offset + extra_buffers_size
- ALIGN(lsmctx.len, sizeof(u64)) /* ALIGN(0,8) */
security_release_secctx() does memset(cp, 0, sizeof(*cp)), so lsmctx.len
reads back as 0 and the subtraction contributes nothing, leaving
sg_buf_end_offset too large by the aligned secctx size on every
transaction to a txn_security_ctx node.
Each BINDER_TYPE_PTR object then derives buf_left = sg_buf_end_offset -
sg_buf_offset as the sole upper bound on its copy, so the inflated end
offset lets the copy run into the bytes that already hold the secctx.
The aligned size must therefore be cached before release rather than
re-read from the now-cleared field. Fix by caching it in
lsmctx_aligned_size at function scope when it is first computed and
subtracting lsmctx_aligned_size instead of re-reading lsmctx.len after
release. Reuse the same value for the earlier buf_offset computation.
binder: cache secctx size before release zeroes it
binder_transaction() bounds the scatter-gather buffer area with
sg_buf_end_offset and subtracts the aligned LSM context size because
the secctx is written at the tail of that area. The subtraction reads
lsmctx.len, but that field has already been cleared by the time the
line runs:
security_secid_to_secctx(secid, &lsmctx) /* lsmctx.len set */
lsmctx_aligned_size = ALIGN(lsmctx.len, sizeof(u64))
extra_buffers_size += lsmctx_aligned_size
...
security_release_secctx(&lsmctx) /* memset zeroes len */
...
sg_buf_end_offset = sg_buf_offset + extra_buffers_size
- ALIGN(lsmctx.len, sizeof(u64)) /* ALIGN(0,8) */
security_release_secctx() does memset(cp, 0, sizeof(*cp)), so lsmctx.len
reads back as 0 and the subtraction contributes nothing, leaving
sg_buf_end_offset too large by the aligned secctx size on every
transaction to a txn_security_ctx node.
Each BINDER_TYPE_PTR object then derives buf_left = sg_buf_end_offset -
sg_buf_offset as the sole upper bound on its copy, so the inflated end
offset lets the copy run into the bytes that already hold the secctx.
The aligned size must therefore be cached before release rather than
re-read from the now-cleared field. Fix by caching it in
lsmctx_aligned_size at function scope when it is first computed and
subtracting lsmctx_aligned_size instead of re-reading lsmctx.len after
release. Reuse the same value for the earlier buf_offset computation.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
|
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Linux Kernel
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Fixes
Solution
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Workaround
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References
History
Sat, 15 Aug 2026 07:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-120 |
Sat, 15 Aug 2026 06:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: binder: cache secctx size before release zeroes it binder_transaction() bounds the scatter-gather buffer area with sg_buf_end_offset and subtracts the aligned LSM context size because the secctx is written at the tail of that area. The subtraction reads lsmctx.len, but that field has already been cleared by the time the line runs: security_secid_to_secctx(secid, &lsmctx) /* lsmctx.len set */ lsmctx_aligned_size = ALIGN(lsmctx.len, sizeof(u64)) extra_buffers_size += lsmctx_aligned_size ... security_release_secctx(&lsmctx) /* memset zeroes len */ ... sg_buf_end_offset = sg_buf_offset + extra_buffers_size - ALIGN(lsmctx.len, sizeof(u64)) /* ALIGN(0,8) */ security_release_secctx() does memset(cp, 0, sizeof(*cp)), so lsmctx.len reads back as 0 and the subtraction contributes nothing, leaving sg_buf_end_offset too large by the aligned secctx size on every transaction to a txn_security_ctx node. Each BINDER_TYPE_PTR object then derives buf_left = sg_buf_end_offset - sg_buf_offset as the sole upper bound on its copy, so the inflated end offset lets the copy run into the bytes that already hold the secctx. The aligned size must therefore be cached before release rather than re-read from the now-cleared field. Fix by caching it in lsmctx_aligned_size at function scope when it is first computed and subtracting lsmctx_aligned_size instead of re-reading lsmctx.len after release. Reuse the same value for the earlier buf_offset computation. | |
| Title | binder: cache secctx size before release zeroes it | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T05:51:18.975Z
Reserved: 2026-07-30T09:28:09.395Z
Link: CVE-2026-68458
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-15T06:18:15.350
Modified: 2026-08-15T06:18:15.350
Link: CVE-2026-68458
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-08-15T07:45:04Z
Weaknesses