# CVE-2026-49834: sigstore-go: Multi-log threshold bypass via single compromised log > A single compromised transparency log can bypass multi-log verification thresholds in the sigstore-go library, undermining supply chain integrity guarantees. - **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 17 Jul 2026 - **Updated:** 17 Jul 2026 - **Also known as:** CLEANSTART-2026-OE12981, CLEANSTART-2026-OY65007, DEBIAN-CVE-2026-49834, GHSA-9vcr-p3rj-q5q6, GO-2026-5952, MINI-24c8-8xp2-pcj5, MINI-25j4-q633-5wq2, MINI-2x3f-qfh9-8fhv, MINI-3vpw-656g-q24w, MINI-4333-3gvm-24wc, MINI-445f-pjp9-4vhj, MINI-47mq-g227-8qw9, MINI-4xjr-r2pg-cff6, MINI-53wf-rq5f-rg3g, MINI-684q-249f-682v, MINI-6j64-c946-786c, MINI-6m8f-xw37-fwc6, MINI-6qhm-c8f7-5j2h, MINI-6rvh-c86p-fx3q, MINI-6vxf-j7hp-425w, MINI-6wvq-vxvh-q3hm, MINI-74pj-rhcg-phrm, MINI-7ghg-47rj-8m7r, MINI-84cf-g2jf-mmgm, MINI-85r6-3qrv-h68h, MINI-898q-fq4q-j7h4, MINI-89vm-w5qw-q47x, MINI-8mf8-wgqc-q4g6, MINI-993w-q5cf-cj32, MINI-9cc3-wc7x-w59v, MINI-c325-v74g-f28h, MINI-c73f-3chh-5qq7, MINI-c7f8-335j-mm7f, MINI-chwg-w7wq-whgh, MINI-cwjg-4h25-57rm, MINI-g4q5-vp6r-w683, MINI-g56x-fjvp-2gm8, MINI-gfh8-pjr5-ghcm, MINI-gh5h-96v6-5mr5, MINI-gvq8-xgwr-hjm7, MINI-h2jw-2h37-6hc8, MINI-h524-v54v-wrg8, MINI-h6m4-4h3w-22xp, MINI-h86f-g9xv-9q55, MINI-hq48-wq3h-p3q8, MINI-hvc9-ph84-p8x8, MINI-j54f-fg72-9f57, MINI-j646-gc5c-f6pm, MINI-jhv6-v5q8-33jp, MINI-jp24-44r5-pg2h, MINI-mh3p-pfrc-h598, MINI-mp6q-wfmm-3vg9, MINI-ppx4-44m8-rpmj, MINI-prq3-6399-m4rj, MINI-q4xx-3g26-fqpf, MINI-q97w-vx9j-mxhg, MINI-qfpw-jpvm-7q3g, MINI-qm36-p858-6rph, MINI-r5g8-r9r5-rxpp, MINI-rqwp-rhp7-7r79, MINI-rxh5-622f-5g2q, MINI-v84p-4267-jpxj, MINI-vjcg-548w-m76p, MINI-vr27-3mj3-88qp, MINI-vv96-9vcq-qxv7, MINI-w6f7-jp3c-8478, MINI-w6qg-fqrf-85w7, MINI-w873-w5f3-rjhx, MINI-wmwh-x878-qm32, MINI-wp69-75wv-hvcg, MINI-wqr3-63m9-g2fg, MINI-x386-xcqj-739w, MINI-xwqj-72jw-hhm4, UBUNTU-CVE-2026-49834 ## What is CVE-2026-49834? CVE-2026-49834 is a medium-severity vulnerability in sigstore-go, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description sigstore-go is a Go library for Sigstore signing and verification. Prior to 1.2.0, a verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) counts verified witnesses per entry or per validation path rather than per log authority, allowing a single compromised transparency log or CT log to satisfy multi-log threshold requirements and defeat the multi-log policy. This issue is fixed in version 1.2.0. Weakness: CWE-347 (Improper Verification of Cryptographic Signature) ## Which versions are affected by CVE-2026-49834? 3 open source packages ship an affected version, including github.com/sigstore/sigstore-go. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/sigstore/sigstore-go` | Go | All versions | 1.2.0 | | `github.com/sigstore/sigstore-go` | Go | All versions | 1.2.0 | | `github.com/sigstore/sigstore-go` | Go | All versions | 1.2.0 | Products: Sigstore Sigstore-Go. ## How do I fix CVE-2026-49834? Upgrade github.com/sigstore/sigstore-go to 1.2.0 or later. ## Is CVE-2026-49834 being exploited? There is no known exploitation of CVE-2026-49834 in the wild and no public exploit code. ## Other vulnerabilities in sigstore-go - [CVE-2024-45395](https://insights.sbomify.com/CVE-2024-45395/): Unbounded loop over untrusted input can lead to endless data attack (low 3.1) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-49834 and fix it if it is affected. What it is: CVE-2026-49834 is a medium-severity vulnerability in sigstore-go, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-49834 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/sigstore/sigstore-go (Go): affected all versions; fixed in 1.2.0 - github.com/sigstore/sigstore-go (Go): affected all versions; fixed in 1.2.0 - github.com/sigstore/sigstore-go (Go): affected all versions; fixed in 1.2.0 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-49834/ (Markdown: https://insights.sbomify.com/CVE-2026-49834/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49834 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49834 - OSV: https://osv.dev/vulnerability/CVE-2026-49834 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-49834/ Summaries are generated and may contain mistakes; the official description above is the record.