CVE-2026-57076

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor.

In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path.

Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor.

In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path.

Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor.

In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path.

Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

YAML::Syck versions before 1.47 for Perl allow a use-after-free and double-free via an anchor node freed while still on the parser value stack YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via a signed-char lookup-table index in syck_base64dec YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len

These are all security issues fixed in the perl-YAML-Syck-1.470.0-1.1 package on the GA media of openSUSE Tumbleweed.

This update for perl-YAML-Syck fixes the following issues:

Changes in perl-YAML-Syck:

• updated to 1.470.0 (1.47) [Security]

  • Fix four libsyck memory-safety CVEs reachable from the default YAML::Syck::Load() path on untrusted input with no special flags (reported by Paul Johnson via CPANSec, PR #213):
    • CVE-2026-57075 (CWE-125): out-of-bounds read in the base64 decoder caused by signed-char indexing of the decode table on !!binary input bsc#1271632
    • CVE-2026-57076 (CWE-416): use-after-free of an anchor key string shared between the node and the anchors table bsc#1271633
    • CVE-2026-57077 (CWE-125): one-byte out-of-bounds read in the lexer newline scan during block-scalar parsing (incomplete-fix follow-on to CVE-2025-11683) bsc#1271634
    • CVE-2026-13713 (CWE-416/CWE-415): use-after-free / double-free of an anchor node on anchor redefinition, a remote-crash DoS from a 7-byte input bsc#1271631
  • Harden syck_base64dec() to bounds-check each read so it cannot run past a non-NUL-terminated input buffer (defense-in-depth for callers passing raw buffers; PR #213) [Bug Fixes]
  • Fix: enforce $MaxDepth on Load to prevent C-stack exhaustion from deeply nested YAML/JSON input; YAML::Syck and JSON::Syck Load now default to 512, matching Dump (PR #204)
  • Fix: emit YAML canonical forms (.nan, .inf, -.inf) for NaN/Inf values in Dump so they roundtrip with ImplicitTyping instead of reloading as plain strings (PR #201) [Maintenance]
  • CI: add an AddressSanitizer job that builds the XS with -fsanitize=address and runs the suite plus the CVE trigger inputs to catch libsyck memory-safety defects; de-pin the libasan version so it tracks the runner's GCC (PR #213)

• updated to 1.460.0 (1.46) [Bug Fixes]

  • Fix: preserve string nature of numeric-looking values in Dump; pure strings (POK only, no IOK/NOK) are now quoted to maintain roundtrip fidelity (GH #199, PR #200)
  • Fix: accept trailing commas in flow sequences and mappings ([a, b,] and {a: 1,}), valid per YAML 1.0/1.1/1.2 spec (GH #195, PR #196)

  [Maintenance]

  • CI: upgrade install-with-cpm to v2 for compatibility with Perl versions prior to 5.24 in perldocker containers (GH #197, PR #198)
  • Clean up MANIFEST.SKIP: add #!include_default, remove redundant entries, exclude .claude/ from distribution

This update for perl-YAML-Syck fixes the following issues:

Changes in perl-YAML-Syck:

• updated to 1.470.0 (1.47) [Security]

  • Fix four libsyck memory-safety CVEs reachable from the default YAML::Syck::Load() path on untrusted input with no special flags (reported by Paul Johnson via CPANSec, PR #213):
    • CVE-2026-57075 (CWE-125): out-of-bounds read in the base64 decoder caused by signed-char indexing of the decode table on !!binary input bsc#1271632
    • CVE-2026-57076 (CWE-416): use-after-free of an anchor key string shared between the node and the anchors table bsc#1271633
    • CVE-2026-57077 (CWE-125): one-byte out-of-bounds read in the lexer newline scan during block-scalar parsing (incomplete-fix follow-on to CVE-2025-11683) bsc#1271634
    • CVE-2026-13713 (CWE-416/CWE-415): use-after-free / double-free of an anchor node on anchor redefinition, a remote-crash DoS from a 7-byte input bsc#1271631
  • Harden syck_base64dec() to bounds-check each read so it cannot run past a non-NUL-terminated input buffer (defense-in-depth for callers passing raw buffers; PR #213) [Bug Fixes]
  • Fix: enforce $MaxDepth on Load to prevent C-stack exhaustion from deeply nested YAML/JSON input; YAML::Syck and JSON::Syck Load now default to 512, matching Dump (PR #204)
  • Fix: emit YAML canonical forms (.nan, .inf, -.inf) for NaN/Inf values in Dump so they roundtrip with ImplicitTyping instead of reloading as plain strings (PR #201) [Maintenance]
  • CI: add an AddressSanitizer job that builds the XS with -fsanitize=address and runs the suite plus the CVE trigger inputs to catch libsyck memory-safety defects; de-pin the libasan version so it tracks the runner's GCC (PR #213)

• updated to 1.460.0 (1.46) [Bug Fixes]

  • Fix: preserve string nature of numeric-looking values in Dump; pure strings (POK only, no IOK/NOK) are now quoted to maintain roundtrip fidelity (GH #199, PR #200)
  • Fix: accept trailing commas in flow sequences and mappings ([a, b,] and {a: 1,}), valid per YAML 1.0/1.1/1.2 spec (GH #195, PR #196)

  [Maintenance]

  • CI: upgrade install-with-cpm to v2 for compatibility with Perl versions prior to 5.24 in perldocker containers (GH #197, PR #198)
  • Clean up MANIFEST.SKIP: add #!include_default, remove redundant entries, exclude .claude/ from distribution