fuzz: zenwebp::demux_container crash (7d80e1b83be72adc) — RECURRED after https://github.com/imazen/zenwebp/issues/81
Open
@lilith is already working on this.
Since Aug 31, 2026.
- Dominant language
- Rust
- Stars
- 15
- Forks
- 1
- PR merge metrics
- No merged PRs in 30d
Description
Found by the continuous fuzz farm (libFuzzer).
This signature was previously filed and closed as fixed at https://github.com/imazen/zenwebp/issues/81 — crashes with the identical panic location kept arriving afterward, so this is either an incomplete fix or a re-break, not a duplicate.
- Crate:
zenwebp - Target:
demux_container - First seen on arch:
x86_64 - Signature (
7d80e1b83be72adc):panic zenwebp/src/mux/demux.rs:364:50 - Repro + metadata in R2:
s3://zenfuzz/crashes/zenwebp/demux_container/x86_64/7d80e1b83be72adc/ - Local mirror:
/mnt/v/fuzzes/_farm/crashes/zenwebp/demux_container/x86_64/4104af98d9dad628
Reproduce:
cd zenwebp
# copy the repro from the R2/local path above, then:
cargo +nightly fuzz run demux_container <repro-file>
Captured trace (tail)
elease/demux_container+0x130bb2) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#17 0x5eb01eaf8800 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x134800) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#18 0x5eb01eafc4b6 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x1384b6) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#19 0x5eb01eaecd1c (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x128d1c) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#20 0x5eb01eaeeb40 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x12ab40) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#21 0x5eb01eaff684 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x13b684) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#22 0x5eb01eb002c8 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x13c2c8) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#23 0x5eb01eafed7d (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x13ad7d) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#24 0x5eb01eb3aea8 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x176ea8) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#25 0x5eb01eb0d731 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x149731) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#26 0x5eb01eb11fde (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x14dfde) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#27 0x5eb01eb002f6 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x13c2f6) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
#28 0x7c4099a2a1c9 (/lib/x86_64-linux-gnu/libc.so.6+0x2a1c9) (BuildId: 328820b908de8ea1ef79afa8995e302e819163d7)
#29 0x7c4099a2a28a (/lib/x86_64-linux-gnu/libc.so.6+0x2a28a) (BuildId: 328820b908de8ea1ef79afa8995e302e819163d7)
#30 0x5eb01ea2e444 (/root/work/zen/zenwebp/fuzz/target/x86_64-unknown-linux-gnu/release/demux_container+0x6a444) (BuildId: 11892ede965f61d75d116fed98a889c188cc4eab)
NOTE: libFuzzer has rudimentary signal handlers.
Combine libFuzzer with AddressSanitizer or similar for better crash reports.
SUMMARY: libFuzzer: deadly signal
────────────────────────────────────────────────────────────────────────────────
Error: Fuzz target exited with exit status: 77
Stack backtrace:
0: anyhow::error::<impl anyhow::Error>::msg
1: cargo_fuzz::project::FuzzProject::exec_fuzz
2: cargo_fuzz::main
3: std::sys::backtrace::__rust_begin_short_backtrace
4: std::rt::lang_start::{{closure}}
5: std::rt::lang_start_internal
6: main
7: <unknown>
8: __libc_start_main
9: _start
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Assessment
This issue has not been assessed yet.