8377526: Update Libpng to 1.6.55

[mrserb]

Hi all,

This pull request contains a backport of commit fd74232d from the openjdk/jdk repository.

The commit being backported was authored by Jayathirth D V on 26 Feb 2026 and was reviewed by Alexander Zvegintsev, Phil Race and Sergey Bylokhov.

Thanks!

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8377526 needs maintainer approval

Issue

• JDK-8377526: Update Libpng to 1.6.55 (Bug - P3 - Approved)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/2643/head:pull/2643
$ git checkout pull/2643

Update a local copy of the PR:
$ git checkout pull/2643
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/2643/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 2643

View PR using the GUI difftool:
$ git pr show -t 2643

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21u-dev/pull/2643.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back serb! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@mrserb This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8377526: Update Libpng to 1.6.55

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 3 new commits pushed to the master branch:

• 9945500: 8377905: gcc.md included with every build
• 0643296: 8287062: com/sun/jndi/ldap/LdapPoolTimeoutTest.java failed due to different timeout message
• 9cb70a7: 8376251: [macos] java/awt/Frame/I18NTitle.java fails on MacOS (JDK-8355884)

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

⚠️ @mrserb This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 00: Full (4e7077d8)

[mrserb]

testing is in progress

[GoeLin]

I ran this through SAPs nightly testing ... all green.

[mrserb]

/approval request
Mostly clean backport. The 3rd-party libpng has been updated to 1.6.55. No new issues found by the JDK desktop tests.

[openjdk]

@mrserb
8377526: The approval request has been created successfully.

[mrserb]

/integrate

[openjdk]

Going to push as commit 2410cdb.
Since your change was applied there have been 4 commits pushed to the master branch:

• 818dd7f: 8378218: MSYS2 reports cygwin triplet causing bash configure failure
• 9945500: 8377905: gcc.md included with every build
• 0643296: 8287062: com/sun/jndi/ldap/LdapPoolTimeoutTest.java failed due to different timeout message
• ... and 1 more: https://git.openjdk.org/jdk21u-dev/compare/101a320ea1cef1077bda8842dd69564632787681...master

Your commit was automatically rebased without conflicts.

[openjdk]

@mrserb Pushed as commit 2410cdb.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.