uuid: Missing buffer bounds check in `v3`/`v5`/`v6` when `buf` is provided

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

uuid is for the creation of RFC9562 (formerly RFC4122) UUIDs. Prior to 14.0.0, v3, v5, and v6 accept external output buffers but do not reject out-of-range writes (small buf or large offset). This allows silent partial writes into caller-provided buffers. This vulnerability is fixed in 14.0.0.

Source published

24 Apr 2026 18:09:24 UTC

Source modified

27 Apr 2026 13:35:34 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 8.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U

uuid before 14.0.0 can make unexpected writes when external output buffers are used, and the UUID version is 3, 5, or 6. In particular, UUID version 4, which is very commonly used, is unaffected by this issue.

Source published

23 Apr 2026 04:00:54 UTC

Source modified

23 Apr 2026 16:22:56 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 3.2 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

uuid before 14.0.0 can make unexpected writes when external output buffers are used, and the UUID version is 3, 5, or 6. In particular, UUID version 4, which is very commonly used, is unaffected by this issue.

Source published

Apr 23, 2026, 4:00:54 AM (timezone not stated)

Source modified

Apr 23, 2026, 4:22:56 PM (timezone not stated)

Observed here

28 Oct 2026 05:11:31 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 3.2 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

uuid is for the creation of RFC9562 (formerly RFC4122) UUIDs. Prior to 14.0.0, v3, v5, and v6 accept external output buffers but do not reject out-of-range writes (small buf or large offset). This allows silent partial writes into caller-provided buffers. This vulnerability is fixed in 14.0.0.

Source published

Apr 24, 2026, 6:09:24 PM (timezone not stated)

Source modified

Apr 27, 2026, 1:35:34 PM (timezone not stated)

Observed here

28 Oct 2026 05:11:15 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 8.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U

uuid is for the creation of RFC9562 (formerly RFC4122) UUIDs. Prior to 14.0.0, v3, v5, and v6 accept external output buffers but do not reject out-of-range writes (small buf or large offset). This allows silent partial writes into caller-provided buffers. This vulnerability is fixed in 14.0.0.

Source published

24 Apr 2026 19:17:14 UTC

Source modified

26 Oct 2026 21:10:00 UTC

Observed here

27 Oct 2026 10:10:19 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

uuid before 14.0.0 can make unexpected writes when external output buffers are used, and the UUID version is 3, 5, or 6. In particular, UUID version 4, which is very commonly used, is unaffected by this issue.

Source published

23 Apr 2026 05:16:05 UTC

Source modified

26 Oct 2026 21:10:00 UTC

Observed here

27 Oct 2026 10:10:19 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 3.2 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS 3.1 · [email protected] · Primary · 2.5 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

### Summary The `v3()`, `v5()`, and `v6()` [API methods](https://github.com/uuidjs/uuid#api-summary) (not `uuid` release versions) accept external output buffers but do not reject out-of-range writes (small `buf` or large `offset`). By contrast, `v4()`, `v1()`, and `v7()` API methods explicitly throw `RangeError` on invalid bounds. This inconsistency allows **silent partial writes** into caller-provided buffers. ### Affected code - `src/v35.ts` (`v3()`/`v5()` path) writes `buf[offset + i]` without bounds validation. - `src/v6.ts` writes `buf[offset + i]` without bounds validation. ### Reproducible PoC ```bash cd /home/StrawHat/uuid npm ci npm run build node --input-type=module -e " import {v4,v5,v6} from './dist-node/index.js'; const ns='6ba7b810-9dad-11d1-80b4-00c04fd430c8'; for (const [name,fn] of [ ['v4()',()=>v4({},new Uint8Array(8),4)], ['v5()',()=>v5('x',ns,new Uint8Array(8),4)], ['v6()',()=>v6({},new Uint8Array(8),4)], ]) { try { fn(); console.log(name,'NO_THROW'); } catch(e){ console.log(name,'THREW',e.name); } }" ``` Observed: - `v4() THREW RangeError` - `v5() NO_THROW` - `v6() NO_THROW` Example partial overwrite evidence captured during audit: ```text same true buf [ 170, 170, 170, 170, 75, 224, 100, 63 ] v6 [ 187, 187, 187, 187, 31, 19, 185, 64 ] ``` ### Security impact - **Primary**: integrity/robustness issue (silent partial output). - If an application assumes full UUID writes into preallocated buffers, this can produce malformed/truncated/partially stale identifiers without error. - In systems where caller-controlled offsets/buffer sizes are exposed indirectly, this may become a security-relevant logic flaw. ### Suggested fix Add the same guard used by `v4()`/`v1()`/`v7()`: ```ts if (offset < 0 || offset + 16 > buf.length) { throw new RangeError(`UUID byte range ${offset}:${offset + 15} is out of buffer bounds`); } ``` Apply to: - `src/v35.ts` (covers `v3()` and `v5()`) - `src/v6.ts`

Source published

22 Apr 2026 20:53:24 UTC

Source modified

10 Sep 2026 03:51:03 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Publisher rating · MODERATE