GO-2026-5024 CVE-2026-39824
Invoking integer overflow in NewNTUnicodeString in golang.org/x/sys/windows
- Severity
- 3.3 / 10
- Low · CVSS 3.1
- Exploit chance (EPSS)
- 0.11%
- Chance of exploitation in the next 30 days. Higher than 1.46% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-190 Integer Overflow or Wraparound
- Fix
0.44.0- Upgrade golang.org/x/sys to this version or later
Description
NewNTUnicodeString does not check for string length overflow. When provided with a string that overflows the maximum size of a NTUnicodeString (a 16-bit number of bytes), it returns a truncated string rather than an error.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| golang.org/x/sys | < 0.44.0 |
0.44.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
golang.org/x/sys Go → 0.44.0
- go
go get golang.org/x/sys@v0.44.0 && go mod tidy
Severity breakdown
CVSS 3.1 3.3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Weakness
CWE-190: Integer Overflow or Wraparound
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
How to prevent it
- Requirements: Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
- Requirements: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482]. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++). [REF-106]
- Implementation: Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range. Use unsigned integers where possible. This makes it easier to perform validation for integer overflows. When signed integers are required, ensure that the range check includes minimum values as well as maximum values.
- Implementation: Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, "not-a-number" calculations, and how the language handles numbers that are too large or too small for its underlying representation. [REF-7] Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.
- Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Implementation: Examine compiler warnings closely and eliminate problems with potential security implications, such as signed / unsigned mismatch in memory operations, or use of uninitialized variables. Even if the weakness is rarely exploitable, a single failure may lead to the compromise of the entire system.
References
Fixes and patches
Issue reports
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-p782-xgp4-8hr8 golang.org/x/sys/unix has Incorrect privilege reporting in syscall | Medium | Also affects golang.org/x/sys |
| GHSA-4642-5mcj-2rqw Forge: ASN.1 OID first arc truncation in asn1.oidToDer | Low | Same weakness, CWE-190 |
| GHSA-4rm8-3hmm-39fg Pillow: Reachable undefined behavior in native integer operations, potentially leading to denial of service or logic integrity compromise | Medium | Same weakness, CWE-190 |
| GHSA-f63g-mx39-3r38 Microsoft Security Advisory CVE-2026-85363 - .NET and Visual Studio Remote Code Execution Vulnerability | High | Same weakness, CWE-190 |
| CVE-2026-97229 Integer Overflow or Wraparound in GitLab | Critical Known exploited | Same weakness, CWE-190 |
| RUSTSEC-2026-0314 Guest can panic host through filesystem datetime overflow | Medium | Same weakness, CWE-190 |
| GHSA-p6m2-r3w9-mpxw rclone local: crafted Range request against a translated symlink panics (DoS) | Medium | Same weakness, CWE-190 |
| EEF-CVE-2026-82737 Ash.Vector wraps the 16-bit dimension header for vectors over 65,535 elements, corrupting data and crashing reads | Not rated yet | Same weakness, CWE-190 |
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