Impact

The affected functions set environment variables without synchronization. On Unix-like operating systems, this can crash in multithreaded programs. Programs may segfault due to dereferencing a dangling pointer if an environment variable is read in a different thread than the affected functions. This may occur without the user's knowledge, notably in the Rust standard library or third-party libraries.

The affected functions from time 0.2.7 through 0.2.22 are:

• time::UtcOffset::local_offset_at
• time::UtcOffset::try_local_offset_at
• time::UtcOffset::current_local_offset
• time::UtcOffset::try_current_local_offset
• time::OffsetDateTime::now_local
• time::OffsetDateTime::try_now_local

The affected functions in time 0.1 (all versions) are:

• time::at_utc
• time::at
• time::now
• time::tzset

Non-Unix targets (including Windows and wasm) are unaffected.

Patches

Pending a proper fix, the internal method that determines the local offset has been modified to always return None on the affected operating systems. This has the effect of returning an Err on the try_* methods and UTC on the non-try_* methods.

Users and library authors with time in their dependency tree should perform cargo update, which will pull in the updated, unaffected code.

Users of time 0.1 do not have a patch and should upgrade to an unaffected version: time 0.2.23 or greater or the 0.3 series.

Workarounds

A possible workaround for crates affected through the transitive dependency in chrono, is to avoid using the default oldtime feature dependency of the chrono crate by disabling its default-features and manually specifying the required features instead.

Examples:

Cargo.toml:

chrono = { version = "0.4", default-features = false, features = ["serde"] }

chrono = { version = "0.4.22", default-features = false, features = ["clock"] }

Commandline:

cargo add chrono --no-default-features -F clock

Sources:

• chronotope/chrono#602 (comment)
• vityafx/serde-aux#21

The Deserialize implementation for VecStorage did not maintain the invariant that the number of elements must equal nrows * ncols. Deserialization of specially crafted inputs could allow memory access beyond allocation of the vector.

This flaw was introduced in v0.11.0 (086e6e) due to the addition of an automatically derived implementation of Deserialize for MatrixVec. MatrixVec was later renamed to VecStorage in v0.16.13 (0f66403) and continued to use the automatically derived implementation of Deserialize.

This flaw was corrected in commit 5bff536 by returning an error during deserialization if the number of elements does not exactly match the expected size.

Lru crate has use after free vulnerability.

Lru crate has two functions for getting an iterator. Both iterators give references to key and value. Calling specific functions, like pop(), will remove and free the value, and but it's still possible to access the reference of value which is already dropped causing use after free.

Affected version of this crate did not properly parse unknown fields when parsing a user-supplied input.

This allows an attacker to cause a stack overflow when parsing the mssage on untrusted data.