MEDIUM5.5

GO-2026-4869

Unbounded allocation for old GNU sparse in archive/tar

Quick fix

GO-2026-4869 — stdlib: upgrade to the fixed version with the command below.

go get stdlib@v1.25.9

Details

tar.Reader can allocate an unbounded amount of memory when reading a maliciously-crafted archive containing a large number of sparse regions encoded in the "old GNU sparse map" format.

Are you affected?

Enter the version of the package you're using.

Affected packages

Go/stdlib

Introduced in: 0Fixed in: 1.25.9

Fixgo get stdlib@v1.25.9

References

https://go.dev/cl/763766[FIX]
https://go.dev/issue/78301[REPORT]
https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU[WEB]