CVE-2026-68433

In the Linux kernel, the following vulnerability has been resolved:

libceph: bound get_version reply decode to front len

handle_get_version_reply() uses msg->front_alloc_len as the decode boundary for MON_GET_VERSION_REPLY. That is the size of the reused reply buffer, not the number of bytes actually received.

A truncated reply can therefore pass ceph_decode_need() and decode the second u64 from stale tail bytes left in the buffer by an earlier message, causing an uninitialized memory read.

Use msg->front.iov_len as the receive-side decode boundary, matching other libceph reply handlers and limiting decoding to the bytes that were actually read from the wire.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/0d934c934ec746d53fc7e4f53239792647bbae63
• https://git.kernel.org/stable/c/1307028f082756bf453e1889aee9983d30643a4b
• https://git.kernel.org/stable/c/340e0386aa39da181015bee38f309018c335ce16
• https://git.kernel.org/stable/c/4e7ebfaa0d14cf50e44041bfde38070d6dbc019f
• https://git.kernel.org/stable/c/72a35070fcefa229b1b031aa7482ad3788e18f07
• https://git.kernel.org/stable/c/d3c32939fa0e3ee9b883b9a0fd1972c5c444e3d0
• https://git.kernel.org/stable/c/d60de8253c85a02d0e6194b0735e7a562981a04c
• https://git.kernel.org/stable/c/f6cbf6878f3a1503c872ba8f1e69a58ee68d8b2e