[github.com/russellhaering/gosaml2] gosaml2 is vulnerable to NULL Pointer Dereference

This affects all versions less than 0.7.0 of package github.com/russellhaering/gosaml2. There is a crash on null pointer dereference caused by sending malformed XML signatures.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-7731
• https://github.com/russellhaering/gosaml2/issues/59
• https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMRUSSELLHAERINGGOSAML2-608302
• https://github.com/advisories/GHSA-gq5r-cc4w-g8xf