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RUSTSEC-2020-0071

MediumCVSS 6.2 / 10
Published Nov 18, 2020·Last modified Feb 4, 2026
Affected Components(0)

No affected components available

Description

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:

Risk Scores
Base Score
6.2

The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the availability of the system.

Threat Intelligence
5.7

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
1.62%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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Medium severity
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