# CVE-2026-22703: Cosign verification accepts any valid Rekor entry under certain conditions > Attackers can bypass Cosign verification by crafting bundles with unrelated Rekor entries, preventing audit of signing events. - **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 10 Jan 2026 - **Updated:** 12 Jan 2026 - **Also known as:** BIT-cosign-2026-22703, CLEANSTART-2026-FC01276, CLEANSTART-2026-PA14127, DEBIAN-CVE-2026-22703, GHSA-whqx-f9j3-ch6m, GO-2026-4309, MINI-22wr-52rr-563f, MINI-24wx-jjw8-mv2q, MINI-2prp-cpxp-fcfc, MINI-54f7-3rhh-j28c, MINI-578c-r8gr-rq77, MINI-749p-chhm-74fh, MINI-74mq-6j55-f3qh, MINI-chgw-9r75-rr2c, MINI-fjqr-p9c9-8pwg, MINI-j8q8-3m8x-57rw, MINI-jmw2-cqj6-x737, MINI-jwf8-q9xx-v994, MINI-mvvr-39m2-hcf7, MINI-q2xr-23h5-6gp6, MINI-q8cv-89q6-7xwv, MINI-rx4q-vcqm-hq2g, MINI-wxfg-8q8c-2q85, MINI-xvxg-wv3c-x8rj, UBUNTU-CVE-2026-22703 ## What is CVE-2026-22703? CVE-2026-22703 is a medium-severity vulnerability in sigstore cosign, published on 10 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4. Weakness: CWE-345 (Insufficient Verification of Data Authenticity) ## Which versions are affected by CVE-2026-22703? 8 open source packages ship an affected version, including github.com/sigstore/cosign/v2, cosign and github.com/sigstore/cosign. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/sigstore/cosign/v2` | Go | All versions | 2.6.2 | | `github.com/sigstore/cosign/v2` | Go | All versions | 2.6.2 | | `github.com/sigstore/cosign/v2` | Go | All versions | 2.6.2 | | `cosign` | Bitnami | From 2.0.0 | 2.6.2, 3.0.4 | | `github.com/sigstore/cosign` | Go | All versions | None | | `github.com/sigstore/cosign/v3` | Go | All versions | 3.0.4 | | `github.com/sigstore/cosign/v3` | Go | All versions | 3.0.4 | | `github.com/sigstore/cosign/v3` | Go | All versions | 3.0.4 | Products: Sigstore Cosign. ## How do I fix CVE-2026-22703? Upgrade github.com/sigstore/cosign/v2 to 2.6.2 or later. ## Is CVE-2026-22703 being exploited? There is no known exploitation of CVE-2026-22703 in the wild and no public exploit code. ## Other vulnerabilities in sigstore cosign - [CVE-2022-35929](https://insights.sbomify.com/CVE-2022-35929/): False positive signature verification in cosign (high 7.1) - [CVE-2022-36056](https://insights.sbomify.com/CVE-2022-36056/): Vulnerabilities with blob verification in sigstore cosign (medium 5.5) - [CVE-2026-39395](https://insights.sbomify.com/CVE-2026-39395/): Cosign's verify-blob-attestation reports false positive when payload parsing fails (medium 4.3) - [CVE-2024-29902](https://insights.sbomify.com/CVE-2024-29902/): Cosign vulnerable to system-wide denial of service via malicious attachments (medium 4.2) - [CVE-2024-29903](https://insights.sbomify.com/CVE-2024-29903/): Cosign vulnerable to machine-wide denial of service via malicious artifacts (medium 4.2) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-22703 and fix it if it is affected. What it is: CVE-2026-22703 is a medium-severity vulnerability in sigstore cosign, published on 10 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-22703 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/sigstore/cosign/v2 (Go): affected all versions; fixed in 2.6.2 - github.com/sigstore/cosign/v2 (Go): affected all versions; fixed in 2.6.2 - github.com/sigstore/cosign/v2 (Go): affected all versions; fixed in 2.6.2 - cosign (Bitnami): affected from 2.0.0; fixed in 2.6.2, 3.0.4 - github.com/sigstore/cosign (Go): affected all versions; no fix listed - github.com/sigstore/cosign/v3 (Go): affected all versions; fixed in 3.0.4 - github.com/sigstore/cosign/v3 (Go): affected all versions; fixed in 3.0.4 - github.com/sigstore/cosign/v3 (Go): affected all versions; fixed in 3.0.4 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-2026-22703/ (Markdown: https://insights.sbomify.com/CVE-2026-22703/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22703 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22703 - OSV: https://osv.dev/vulnerability/CVE-2026-22703 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-22703/ Summaries are generated and may contain mistakes; the official description above is the record.