CVE-2026-84267
Gvfs: sftp: uninitialized heap disclosure in read_string()
What happened?
A flaw was found in the SFTP backend in gvfs. When mounting a share, a malicious SFTP server can cause read_string() to allocate a buffer with a certain length but the function does not verify that the buffer is completely filled, leaving the remainder of the buffer containing uninitialized heap contents. If the server sends a short FXP_HANDLE reply, these uninitialized bytes are taken as the file handle. The client will then echo these uninitialized bytes back to the server on all subsequent requests using that handle. With a length of 128 bytes, this issue allows the malicious server to deterministically read uninitialized heap memory from the gvfsd-sftp process, leaking its heap base and the load address of the libgio library, resulting in a deterministic defeat of Address Space Layout Randomization (ASLR).
Affected software and versions
| Software | Version information | Fixed version |
|---|---|---|
| gvfsGNOME | affected: 1.10.0 to < 1.60.2 | See vendor advisory |
| gvfsRed Hat | Default status: affected | See vendor advisory |
| gvfsRed Hat | Default status: unknown | See vendor advisory |
| gvfsRed Hat | Default status: affected | See vendor advisory |
| gvfsRed Hat | Default status: affected | See vendor advisory |
| gvfsRed Hat | Default status: affected | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.