CVE-2020-26235

Segmentation fault in time

Workarounds

Library authors must ensure that the program only has one running thread at the time of calling any affected method. Binary authors may do the same and/or ensure that no other thread is actively mutating the environment.

References

time-rs/time#293.

Unix-like operating systems may segfault due to dereferencing a dangling pointer in specific circumstances. This requires an environment variable to be set in a different thread than the affected functions. This may occur without the user's knowledge, notably in a third-party library.

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:

• at
• at_utc
• now

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

The application dereferences a null pointer, causing a crash. Typical impact: denial of service via crash.

CVE-2020-26235 has a CVSS score of 6.2 (Medium). The vector is requires local access, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.2.23); upgrading removes the vulnerable code path.

Kodem intelligence

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In some versions of time, 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. In later versions, time will attempt to determine the number of threads running in the process. If the process is single-threaded, the call will proceed as its safety invariant is upheld.

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

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

1. What is CVE-2020-26235? CVE-2020-26235 is a medium-severity null pointer dereference vulnerability in time (rust), affecting versions >= 0.2.7, < 0.2.23. It is fixed in 0.2.23. The application dereferences a null pointer, causing a crash.
2. How severe is CVE-2020-26235? CVE-2020-26235 has a CVSS score of 6.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of time are affected by CVE-2020-26235? time (rust) versions >= 0.2.7, < 0.2.23 is affected.
4. Is there a fix for CVE-2020-26235? Yes. CVE-2020-26235 is fixed in 0.2.23. Upgrade to this version or later.
5. Is CVE-2020-26235 exploitable, and should I be worried? Whether CVE-2020-26235 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2020-26235 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2020-26235?
   • Upgrade time to 0.2.23 or later
   • Upgrade time to 0.2.23 or later

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