CVE-2016-1977

What it actually does

The flaw triggers stack memory corruption inside Graphite 2's set_ref function during analysis of a crafted smart font, allowing an attacker to overwrite return addresses or data structures and achieve arbitrary code execution or a denial of service.

Why it matters to the business

Organizations running the listed kots packages risk remote compromise or service disruption when untrusted fonts are processed, which can lead to full system takeover or application crashes in any downstream component that depends on these packages.

How an attack unfolds

An attacker prepares a malicious Graphite font file and causes a victim application to load it (for example through a web page, document, or font directory); the vulnerable decoder processes the font, corrupts the stack, and either crashes the process or executes attacker-supplied code.

How to fix it

Upgrade kots (Chainguard) to 1.109.14-r1, kots (Wolfi) to 1.109.14-r1, kots-symlink-compat (Chainguard) to 1.109.14-r1, and kots-symlink-compat (Wolfi) to 1.109.14-r1; rebuild and redeploy any containers or packages that depend on the vulnerable Graphite 2 library.

How to confirm the fix worked

Confirm installed package versions meet or exceed the listed fixed releases, run regression tests that exercise font loading paths, and verify that Graphite 2 version 1.3.6 or newer is present in the final artifacts.

Typical attack path

1. Prepare and host a specially crafted Graphite smart font
2. Lure the target into loading the font via browser, document viewer, or application
3. Trigger the set_ref analysis path inside Graphite 2
4. Leverage the resulting stack corruption to execute code or crash the process

How to detect it

Review application and system logs for unexpected crashes or segmentation faults that occur during font loading; inspect process memory dumps or core files for signs of stack corruption around Graphite font decoder routines.

What your security team should do

• Apply the listed package upgrades immediately in all environments that include the affected kots components
• Remove or sandbox any legacy font-processing code paths that still rely on Graphite 2
• Add package-version checks to CI/CD pipelines to prevent reintroduction of vulnerable Graphite versions