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CVE-2021-3782

MEDIUMCVSS 6.6/10EPSS 0.29%

Last modified

CVE-2021-3782 is a medium-severity vulnerability rated 6.6/10 on the CVSS scale. An internal reference count is held on the buffer pool, incremented every time a new buffer is created from the pool. The reference count is maintained as an int; on LP64 systems this can cause the reference count to overflow if the client creates a large number of wl_shm buffer objects, or if it can coerce the server to create a large number of external references to the buffer storage. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

Description

An internal reference count is held on the buffer pool, incremented every time a new buffer is created from the pool. The reference count is maintained as an int; on LP64 systems this can cause the reference count to overflow if the client creates a large number of wl_shm buffer objects, or if it can coerce the server to create a large number of external references to the buffer storage. With the reference count overflowing, a use-after-free can be constructed on the wl_shm_pool tracking structure, where values may be incremented or decremented; it may also be possible to construct a limited oracle to leak 4 bytes of server-side memory to the attacking client at a time.

Metrics

CVSS 3.1
6.6/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H

EPSS Probability
0.29%

21.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
WaylandWayland< 1.20.91

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-3782?
An internal reference count is held on the buffer pool, incremented every time a new buffer is created from the pool. The reference count is maintained as an int; on LP64 systems this can cause the reference count to overflow if the client creates a large number of wl_shm buffer objects, or if it can coerce the server to create a large number of external references to the buffer storage. With the reference count overflowing, a use-after-free can be constructed on the wl_shm_pool tracking structure, where values may be incremented or decremented; it may also be possible to construct a limited oracle to leak 4 bytes of server-side memory to the attacking client at a time.
How severe is CVE-2021-3782?
CVE-2021-3782 has a CVSS score of 6.6/10 (MEDIUM severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.
How do I fix CVE-2021-3782?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3782?

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Source: NVD / NIST