diff --git a/.github/scripts/release-notes.ts b/.github/scripts/release-notes.ts
index d7c337e8..9c585848 100644
--- a/.github/scripts/release-notes.ts
+++ b/.github/scripts/release-notes.ts
@@ -55,8 +55,12 @@ if (!repoUrl) {
   console.error('CHANGELOG.md needs a "[Unreleased]: <repo url>/compare/..." link ref at the bottom')
   process.exit(1)
 }
-// The previous release is the next version heading down (the changelog is newest first).
-const previous = /^## \[([^\]]+)\]/.exec(lines[end] ?? "")?.[1]
+// The previous release is the next version heading down that has a tag (the changelog is newest first).
+// A heading for a version that never shipped (its CI or Publish failed) has no tag, so it is skipped.
+const previous = lines
+  .slice(end)
+  .map((l) => /^## \[([^\]]+)\]/.exec(l)?.[1])
+  .find((v): v is string => v !== undefined && v !== "Unreleased" && refExists(`v${v}`))
 
 // Before the tag exists (a dry run from main) the commits are the ones on HEAD.
 const tag = `v${version}`
diff --git a/.github/scripts/release.ts b/.github/scripts/release.ts
index c2301c3c..e0673267 100644
--- a/.github/scripts/release.ts
+++ b/.github/scripts/release.ts
@@ -37,7 +37,7 @@ import { existsSync, mkdirSync, mkdtempSync, readFileSync, rmSync, writeFileSync
 import { tmpdir } from "node:os"
 import { join } from "node:path"
 import semver from "semver"
-import { changelogBlock, collectCommits } from "./commit-detail.ts"
+import { changelogBlock, collectCommits, refExists } from "./commit-detail.ts"
 import { approvalState, judgeChecks, mergeRules, type CheckRow, type GhReview } from "./merge-gate.ts"
 import { bumpInstallPins, replaceSinceNext } from "./since-next.ts"
 
@@ -516,7 +516,17 @@ const docRewrites = ["README.md", ...[...new Bun.Glob("docs/**/*.md").scanSync("
 const linkAt = lines.findIndex((l) => l.startsWith("[Unreleased]: "))
 const link = /^\[Unreleased\]: (.+)\/compare\/v(.+)\.\.\.HEAD$/.exec(lines[linkAt] ?? "")
 if (!link) fail('CHANGELOG.md needs a "[Unreleased]: <repo url>/compare/v<previous>...HEAD" link ref at the bottom')
-const [, repoUrl, previous] = link
+const [, repoUrl, linkedPrevious] = link
+// The link names the last version the changelog saw, but an unpublished version (a release whose CI or
+// Publish failed) leaves a heading and link for a tag that does not exist, and the next release then fails
+// on `git log v<that>..HEAD`. So the previous version is the newest tag that exists below this release.
+const previous = refExists(`v${linkedPrevious}`)
+  ? linkedPrevious
+  : git("tag", "--list", "v*", "--sort=-v:refname")
+      .split("\n")
+      .map((t) => t.slice(1))
+      .find((v) => semver.valid(v) && semver.lt(v, version))
+if (!previous) fail(`no release tag below ${version} exists, and CHANGELOG.md links v${linkedPrevious}, which is not a tag`)
 if (!semver.gt(version, previous)) fail(`${version} does not increase on the last released version ${previous}`)
 
 // The commit-level detail: every commit since the previous tag, grouped by type, in a