GoApplication · Golang
CVE-2026-27143
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedArithmetic over induction variables in loops were not correctly checked for underflow or overflow. As a result, the compiler would allow for invalid indexing to occur at runtime, potentially leading to memory corruption.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis is a compiler vulnerability where arithmetic operations on induction variables (loop counters) are not properly validated for integer underflow or overflow. When the compiler fails to detect these arithmetic errors, it can generate code that performs invalid memory indexing, leading to potential memory corruption at runtime.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
GoApplication
< 1.25.9>= 1.26.0, < 1.26.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed Go compiler versionRun 'go version' to see the Go version numberAffected if The version shown is less than 1.25.9, or greater than or equal to 1.26.0 but less than 1.26.2
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Identify loops with arithmetic on counter variablesAudit your codebase for 'for' loops where the induction variable (loop counter) has arithmetic operations performed on it within the loop body, such as 'i++', 'i += n', or 'i = i + n' where n is a variableAffected if Your code contains loops where arithmetic on the loop counter could overflow given extreme but valid inputs
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Check if compiling untrusted third-party codeDetermine whether your build pipeline compiles code from untrusted sources or allows user-supplied Go code to be compiledAffected if You compile untrusted Go code using the affected Go compiler version
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Verify memory-safe indexing patterns in loopsReview loop-heavy code for array/slice indexing that uses the loop counter or arithmetic derived from it, and verify bounds checking is not bypassedAffected if Code uses loop counter arithmetic to index arrays/slices without explicit bounds checks
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Review compiled binary behaviorIf you have binaries compiled with the affected Go versions, test them with extreme loop iteration counts to observe if unexpected behavior or memory corruption occursAffected if Programs exhibit memory corruption or crashes when given large iteration counts in loops with counter arithmetic
You are affected if your Go compiler version is in the range < 1.25.9 or >= 1.26.0 < 1.26.2 AND you compile code that uses loops with arithmetic operations on induction variables.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.25.91.26.2
Update the affected compiler to a version with the overflow/underflow check fix. Then recompile all code that was previously built with the vulnerable compiler version, as existing binaries may contain the memory corruption vulnerability.
Go 1.25.9 (for 1.25.x branch) or Go 1.26.2 (for 1.26.x branch)
- 1. Check current Go version by running: go version
- 2. If using Go 1.25.x and version < 1.25.9, upgrade to Go 1.25.9 or later
- 3. If using Go 1.26.0 or 1.26.1, upgrade to Go 1.26.2 or later
- 4. Download the latest Go release from https://go.dev/dl/
- 5. Verify the upgrade was successful by running: go version
- 6. Rebuild and test your application to ensure the compiler fix resolves the loop induction variable overflow issue
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Go
Scoped from the published advisory
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-27143 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-27143 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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