How severe is CVE-2023-23626?

CVE-2023-23626 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-23626?

CVE-2023-23626 affects the following packages: github.com/ipfs/go-bitfield (Go). Ecosystems affected: Go.

How do I fix CVE-2023-23626?

Update github.com/ipfs/go-bitfield to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-23626 is resolved across your whole dependency graph.

How do I detect CVE-2023-23626 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/ipfs/go-bitfield, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-23626 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2023-23626 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2023-23626, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-23626?

CVE-2023-23626 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 60th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-23626?

CVE-2023-23626 is classified as CWE-754 (CWE-754), CWE-1284 (CWE-1284). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-23626 published, and has it been updated?

CVE-2023-23626 was published on February 9, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2023-23626 — go-bitfield

MEDIUMFix: ipfs/go-bitfield@5e1d256

CVE-2023-23626 is a medium-severity (CVSS 5.9) CWE-754 vulnerability in github.com/ipfs/go-bitfield. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for github.com/ipfs/go-bitfield — see the affected versions and patch details below.

Denial of service when feeding malformed size arguments in go-bitfield

Also known asGHSA-2h6c-j3gf-xp9rGO-2023-1558

Published

Feb 9, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-23626.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs60th percentile — riskier than 60% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐹github.com/ipfs/go-bitfield

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

When feeding untrusted user input into the size parameter of NewBitfield and FromBytes functions, an attacker can trigger panics.

This happen when the size is a not a multiple of 8 or is negative. There were already a note in the NewBitfield documentation:

Panics if size is not a multiple of 8.

But it incomplete and missing from FromBytes's documentation.

This has been replaced by returning an (Bitfield, error) and returning a non nil error if the size is wrong.

Patches

https://github.com/ipfs/go-bitfield/commit/5e1d256fe043fc4163343ccca83862c69c52e579

Workarounds

Ensure size%8 == 0 && size >= 0 yourself before calling NewBitfield or FromBytes

References

https://github.com/ipfs/go-unixfs/security/advisories/GHSA-q264-w97q-q778

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/ipfs/go-bitfield`	all versions	1.1.0`go get github.com/ipfs/go-bitfield@v1.1.0`

Affected Products

1 product · 1 configurations

Application

go-bitfieldprotocol

< 1.1.0

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

go-bitfield is a simple bitfield package for the go language aiming to b…

github.comNVDFeb 2023

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/ipfs/go-bitfield, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/ipfs/go-bitfield to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-23626 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact When feeding untrusted user input into the size parameter of `NewBitfield` and `FromBytes` functions, an attacker can trigger `panic`s. This happen when the `size` is a not a multiple of `8` or is negative. There were already a note in the `NewBitfield` documentation: > ``` > Panics if size is not a multiple of 8. > ```` But it incomplete and missing from `FromBytes`'s documentation. This has been replaced by returning an `(Bitfield, error)` and returning a non nil error if the size is wrong. ### Patches - https://github.com/ipfs/go-bitfield/commit/5e1d256fe043fc4163343ccca83862